Item 1. Business

We help people experience the world by providing consumers, travel service providers and restaurants with leading travel and restaurant reservation and related services. Through our online travel companies ("OTCs"), we connect consumers wishing to make travel reservations with providers of travel services around the world. We are the leader in the worldwide online accommodation reservation market based on room nights booked. We offer consumers a broad array of accommodation reservations (including hotels, bed and breakfasts, hostels, apartments, vacation rentals and other properties) through our Booking.com, priceline.com and agoda.com brands. Our priceline.com brand also offers consumers reservations for rental cars, airline tickets, vacation packages and cruises. We offer rental car reservations worldwide through rentalcars.com. We also allow consumers to easily compare airline ticket, hotel reservation and rental car reservation information from hundreds of travel websites at once through KAYAK. We provide restaurants with reservation management services and consumers with the ability to make restaurant reservations at participating restaurants through OpenTable, a leading provider of online restaurant reservations.

We launched our business in the United States in 1998 under the priceline.com brand and have since expanded our operations to include five other primary, independently operated brands: Booking.com, KAYAK, agoda.com, rentalcars.com and OpenTable. Our mission is to help people experience the world by serving both consumers and our travel service provider and restaurant partners with worldwide leadership in online reservation and related services. Our business is driven primarily by international results, which consist of the results of Booking.com, agoda.com and rentalcars.com and the results of the internationally-based websites of KAYAK and OpenTable (in each case regardless of where the consumer resides, where the consumer is physically located while making a reservation or the location of the travel service provider or restaurant). During the year ended December 31, 2015, our international business (the substantial majority of which is generated by Booking.com) represented approximately 88% of our gross bookings (an operating and statistical metric referring to the total dollar value, generally inclusive of all taxes and fees, of all travel services booked by our customers, net of cancellations), approximately 86% of our consolidated gross profit and approximately 94% of our consolidated operating income. A significant majority of our gross profit is earned in connection with facilitating accommodation reservations. See Note 17 to the Consolidated Financial Statements for more geographic information.

The Priceline Group Inc. was formed as a Delaware limited liability company in 1997 and was converted into a Delaware corporation in July 1998. On April 1, 2014, the Company changed its name from priceline.com Incorporated to The Priceline Group Inc. Our common stock is listed on the NASDAQ Global Select Market under the symbol "PCLN." Our principal executive offices are located at 800 Connecticut Avenue, Norwalk, Connecticut 06854. We refer to our company and all of our subsidiaries and brands, including Booking.com, priceline.com, KAYAK, agoda.com, rentalcars.com, OpenTable and various smaller brands, collectively as "The Priceline Group," the "Company," "we," "our" or "us." We determined that our brands constitute our operating segments. We have aggregated our operating segments into one reportable segment. See Note 2 to our Consolidated Financial Statements.

The Priceline Group Business Model

We derive substantially all of our gross profit from the following sources:

•	Commissions earned from facilitating reservations of accommodations, rental cars, cruises and other travel services;

•	Transaction gross profit and customer processing fees from our accommodation, rental car, airline ticket and vacation package reservation services;

•	Beginning on May 21, 2013, advertising revenues primarily earned by KAYAK from sending referrals to OTCs and travel service providers, as well as from advertising placements on KAYAK's websites and mobile apps;

•	Beginning on July 24, 2014, revenues recognized by OpenTable, which consist of reservation revenues (reservation fees paid by restaurants for diners seated through OpenTable's online reservation service), subscription fees for restaurant reservation management services and other revenues; and

•	Damage excess waiver fees, travel insurance fees and global distribution system ("GDS") reservation booking fees, in each case related to certain of our travel services.

Our priceline.com brand offers merchant Name Your Own Price® opaque travel services, which are recorded in revenue on a "gross" basis and have associated cost of revenue. All of our other services are recorded in revenue on a "net" basis and have no associated cost of revenue. Therefore, revenue increases and decreases are impacted by changes in the mix of our revenues between Name Your Own Price® travel services and other services. Gross profit reflects the commission or net margin earned for all of our services. Consequently, gross profit is an important measure to evaluate growth in our business because, in contrast to our revenues, it is not affected by the different methods of recording revenue and cost of revenue between our Name Your Own Price® travel reservation services and our other services.

For the year ended December 31, 2015, we had gross profit of approximately $8.6 billion comprised of "agency" gross profit, "merchant" gross profit, and "other" gross profit. Agency gross profit is derived from travel-related transactions where we are not the merchant of record, and therefore do not charge the customer's credit card, and where the prices of the travel services are determined by third parties. Agency gross profit, which represented the substantial majority of our total gross profit in 2015, consists primarily of: (1) travel commissions; (2) GDS reservation booking fees related to certain travel services; (3) travel insurance fees; and (4) customer processing fees. Merchant gross profit is derived from services where we are the merchant of record and therefore charge the consumer's credit card for the travel services provided, and consists of: (1) transaction gross profit representing the amount charged to a consumer, less the amount charged to us by travel service providers; (2) customer processing fees; and (3) ancillary fees, including damage excess waiver and travel insurance fees and GDS reservation booking fees related to certain travel services. Advertising and other revenues are derived primarily from (1) revenues earned by KAYAK for (a) sending referrals to OTCs and travel service providers and (b) advertising placements on KAYAK's websites and mobile apps; and (2) revenues earned by OpenTable for (a) reservation fees paid by restaurants for diners seated through OpenTable's online reservation service and (b) subscription fees earned by OpenTable for restaurant reservation management services. Revenues from KAYAK are net of intercompany revenues earned by KAYAK from other Priceline Group brands. See Note 2 to our Consolidated Financial Statements for more information.

The Priceline Group Strategy

We aim to achieve our mission to help people experience the world through global leadership in online travel and restaurant reservation and related services. We focus on relentless innovation and a commitment to serve both consumers and travel service provider and restaurant partners with unmatched service and best-in-class digital technology. As the online travel and dining categories continue to grow as consumer purchasing shifts from traditional off-line channels to interactive online channels, including mobile channels, our strategy is to continue to participate broadly in this online growth by expanding our service offerings and markets. In particular, we aim to be the world leader in online travel and restaurant reservation and related services by (a) providing consumers with the best experience, (b) partnering with travel service providers and restaurants to our mutual benefit, (c) operating entrepreneurial, independent brands that share best practices, and (d) investing in profitable and sustainable growth.

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Providing the best consumer experience. We believe that offering consumers an outstanding online experience is essential for our future success. To accomplish this, we focus on providing consumers with: a variety of intuitive, easy-to-use online travel and restaurant reservation and search services; a continually increasing number, location and variety of accommodations available through our services: informative and useful content, such as pictures, accommodation details and reviews; and excellent customer service. For example, Booking.com increasingly provides reservation services for accommodations other than hotels, such as vacation rentals. Booking.com included over 850,000 properties on its website as of February 15, 2016, which included

approximately 390,000 vacation rental properties (updated property counts are available on the Booking.com website). Further, we endeavor to provide excellent customer service in a variety of ways, including through our call centers and websites, so that consumers can be confident that booking reservations through us will lead to a positive experience. We are constantly innovating in order to provide a best-in-class user experience with intuitive, easy-to-use websites and mobile apps to ensure that we are meeting the needs of online consumers while aiming to exceed their expectations.

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Partnering with travel service providers and restaurants. We aim to establish mutually beneficial relationships with travel service providers and restaurants around the world. We believe that travel service providers and restaurants can benefit from participating in our services by increasing their distribution channels, demand and inventory utilization in an efficient and cost-effective manner. Travel service providers and restaurants benefit from our well-known brands and online marketing efforts, expertise in offering an excellent consumer experience through our websites and mobile apps and ability to offer their inventory in markets and to consumers that the travel service provider or restaurant may be unable or unlikely to reach. For example, an independent hotel may not have the means or expertise to market itself to international travelers, including in other languages, to build and operate effective desktop and mobile websites and online reservation services, or to engage in sophisticated online marketing techniques. Further, we are increasingly providing services, other than reservations booked through our websites and mobile apps, designed to help our partners grow their business. For example, Booking.com's BookingSuite services are designed to offer accommodation providers with affordable and effective marketing and business analytics tools to help them attract guests and increase their profitability. Similarly, OpenTable is continuously working to improve its reservation management software services to help restaurants more effectively manage their reservations and more efficiently market their available tables to diners.

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Maintaining multiple, independently managed brands. We employ a strategy of operating multiple, independently managed brands, which we believe allows us the opportunity to offer our reservation services in ways that appeal to different consumers while maintaining an entrepreneurial, competitive spirit among our brands. We intend to invest resources to support organic growth by all of our brands, whether through increased advertising, geographic expansion, technology innovation or increased access to accommodations, rental cars, restaurants or other services. We also believe that by operating independently managed brands, we encourage innovation and experimentation by our brands, which allows us to more quickly discern and adapt to changing consumer behaviors and market dynamics. Although our brands are independently operated, we intend to continue to share best practices, access to services and customers across our brands. We believe that by promoting our brands worldwide, sharing accommodation reservation availability and customer flow, and applying our industry experiences across brands and markets, we can more effectively expand our reservation services globally and maintain and grow our position as a leading provider of worldwide online travel and restaurant reservation and related services.

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Investing in profitable and sustainable growth. Our strategy is to ensure that we offer online services that meet the needs and expectations of both consumers and travel service providers and restaurants and that we believe are or will be likely to result in long-term profitability and growth. We intend to accomplish this through continuous investment and innovation in growing our businesses in new and current markets, expanding our services and ensuring that we provide an appealing, intuitive and easy-to-use consumer experience through our websites and mobile applications. We also may pursue strategic transactions. For example, in 2013 we entered the meta-search business when we acquired KAYAK and in 2014 we entered the online restaurant reservation market when we acquired OpenTable. We regularly evaluate, and may pursue and consummate, other potential strategic acquisitions, partnerships, joint ventures or investments, whether to expand our businesses into complementary areas, expand our current businesses, acquire innovative technology or for other reasons. For example, in 2014 and 2015 we strengthened our commercial partnership with, and made significant financial investments in, Ctrip, a leading OTC operating primarily in China.

Service Offerings

Through our online travel reservation services, we connect consumers wishing to make travel reservations with providers of travel services around the world. We offer consumers a broad array of accommodation reservations (including hotels, bed and breakfasts, hostels, apartments, vacation rentals and other properties) through our Booking.com, priceline.com and agoda.com brands. Our priceline.com brand also offers consumers reservations for rental cars, airline tickets, vacation packages and cruises. We offer rental car reservations worldwide through rentalcars.com. We also allow consumers to easily compare airline ticket, hotel reservation and rental car reservation information from hundreds of travel websites at once through

KAYAK. We provide restaurants with reservation management services and consumers with the ability to make restaurant reservations at participating restaurants through OpenTable.

Booking.com. Booking.com is the world's leading brand for booking online accommodation reservations, based on room nights booked, with operations worldwide and headquarters in the Netherlands. As of February 15, 2016, Booking.com offered accommodation reservation services for over 850,000 properties in over 220 countries and territories on its various websites and in 42 languages, which includes approximately 390,000 vacation rental properties (updated property counts are available on the Booking.com website). Vacation rentals generally consist of, among others, properties categorized as single-unit and multi-unit villas, apartments, "aparthotels" (which are apartments with a front desk and cleaning service) and chalets and are generally self-catered (i.e., include a kitchen), directly bookable properties. Accommodation providers participate in Booking.com, which operates primarily under an agency model, by filing rates and information about the property in Booking.com's proprietary extranet. In addition, Booking.com offers website and other marketing services and business analytics to accommodation providers as part of its BookingSuite initiative.

Priceline.com. Priceline.com offers online travel reservation services primarily in the United States and is headquartered in Norwalk, Connecticut. Through priceline.com, we offer consumers hotel, rental car and airline ticket reservation services, as well as vacation packages and cruises. Priceline.com is a leader in the "opaque" travel reservation business through its pioneering Name Your Own Price® and Express Deals® discount hotel, rental car and airline reservation services. We describe our Name Your Own Price® and Express Deals® discount travel services as "opaque" because certain elements of the service, including the identity of the travel service provider, are not disclosed to the consumer prior to making a reservation. We believe that the combination of priceline.com's retail and opaque models allows it to provide a broad array of options to value-conscious consumers.

KAYAK. KAYAK, headquartered in Stamford, Connecticut, provides an online price comparison service (often referred to as "meta-search") that allows consumers to easily search and compare travel itineraries and prices, including airline ticket, accommodation reservation and rental car reservation information, from hundreds of travel websites at once. KAYAK derives revenues from advertising placements on its websites and mobile apps and from sending referrals to travel service providers and OTCs. KAYAK offers its services in approximately 40 countries, with the United States being its largest market.

Agoda.com. Agoda.com is a leading online accommodation reservation service catering primarily to consumers in the Asia-Pacific region, with headquarters in Singapore and operations in Bangkok, Thailand and throughout the region. Accommodation providers participate in agoda.com, which operates primarily under a merchant model, by filing rates and information about the property in agoda.com's proprietary extranet.

Rentalcars.com. Rentalcars.com is a leading worldwide online rental car reservation service and is headquartered in Manchester, England. Rentalcars.com offers a primarily merchant, online retail and opaque rental car reservation service allowing consumers to make rental car reservations in approximately 46,000 locations throughout the world, with customer support provided in 40 languages. Consumers using rentalcars.com can book a full range of vehicles online through rentalcars.com's website or mobile app, or they can reserve their cars by phone.

OpenTable. In July 2014, we acquired OpenTable, a leading brand for booking online restaurant reservations. Headquartered in San Francisco, California, OpenTable provides online restaurant reservation services to consumers and reservation management services to restaurants. OpenTable does business primarily in the United States, though it intends to continue to invest in expanding its international offerings.

Marketing and Brand Awareness

Booking.com, priceline.com, KAYAK, agoda.com, rentalcars.com and OpenTable have established widely used and recognized e-commerce brands through aggressive marketing and promotion campaigns. Both our online advertising expense and offline advertising expense have increased significantly in recent years, a trend we expect to continue. During 2015, our total online advertising expense was approximately $2.8 billion, primarily related to the use of online search engines (primarily Google), meta-search and travel research services and affiliate marketing to generate traffic to our websites. We also invested approximately $215 million in offline advertising during that period. We intend to continue a strategy of aggressively promoting brand awareness, primarily through online means although we also intend to increase our offline advertising efforts, including by expanding offline campaigns into additional markets. For example, building on its first offline advertising campaign, which it launched in the United States in 2013, Booking.com has begun offline advertising campaigns in other markets, including Australia, Canada, the United Kingdom, Germany, France, Brazil and Japan. We expense the substantial majority of our advertising activities as the expense is incurred, which is typically in the quarter in which reservations are

booked, but recognize most of our gross profit when the consumer's travel or dining experience is completed. As a result, online advertising expense may not be recognized in the same period as the associated gross profit.

Competition

We compete with both online and traditional travel and restaurant reservation and related services. The markets for the services we offer are intensely competitive, a trend we expect to continue, and current and new competitors can launch new services at a relatively low cost. Some of our current and potential competitors, such as Google, Apple, Alibaba, Amazon and Facebook, have access to significantly greater and more diversified resources than we do, and they may be able to leverage other aspects of their businesses (e.g., search or mobile device businesses) to enable them to compete more effectively with us. For example, Google has entered various aspects of the online travel market through its acquisition in 2011 of ITA Software, Inc., a major flight information software company, its hotel search and reservation booking business ("Book on Google") and its license of hotel-booking software from Room 77.

We currently, or potentially may in the future, compete with a variety of companies, including:

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online travel reservation services such as Expedia, Hotels.com, Hotwire, Orbitz, Travelocity, Wotif, Cheaptickets, ebookers, HotelClub, RatesToGo, CarRentals.com and Venere, which are owned by Expedia; laterooms, which is owned by Tui Travel; Hotel Reservation Service (HRS) and hotel.de, which are owned by Hotel Reservation Service; and AutoEurope, Car Trawler, Ctrip (in which we hold a minority interest), eLong (in which Ctrip has acquired a significant minority ownership interest), MakeMyTrip, Webjet, Rakuten, Jalan, Hotel Urbano (in which we hold a minority interest), ViajaNet, Submarino Viagens, Despegar/Decolar, 17u.com, HotelTonight, Bookit.com, CheapOair, Mr. and Mrs. Smith and eDreams ODIGEO;

•	online accommodation search and/or reservation services, such as Airbnb and HomeAway (which is owned by Expedia), currently focused on vacation rental properties and other non-hotel accommodations, including individually owned properties;

•	large online companies, including search, social networking and marketplace companies such as Google, Facebook, Alibaba and Groupon;

•	traditional travel agencies, wholesalers and tour operators, many of which combine physical locations, telephone services and online services, such as Carlson Wagonlit, American Express, Thomas Cook and Tui Travel, as well as thousands of individual travel agencies around the world;

•	travel service providers such as accommodation providers, rental car companies and airlines, many of which have their own branded websites to which they drive business, including joint efforts by travel service providers such as Room Key, an online hotel reservation service owned by several major hotel companies;

•	online travel search and price comparison services (generally referred to as "meta-search" services), such as TripAdvisor, trivago (in which Expedia holds a majority ownership interest), Qunar (which is controlled by Ctrip), Skyscanner, HotelsCombined and Traveloka;

•	online restaurant reservation services, such as TripAdvisor's LaFourchette, Yelp's SeatMe, Zomato, Bookatable (which is owned by Michelin) and Quandoo (which is owned by Recruit); and

•	companies offering new rental car business models or car- or ride-sharing services that affect demand for rental cars, some of which have developed innovative technologies to improve efficiency of point-to-point transportation and extensively utilize mobile platforms, such as Uber, Lyft, Gett, Zipcar (which is owned by Avis), BlaBlaCar, Didi Kuaidi and Ola.

TripAdvisor, a leading travel research and review website, Google, the world's largest search engine, and other large, established companies with substantial resources and expertise in developing online commerce and facilitating Internet traffic have launched search, meta-search and/or reservation booking services and may create additional inroads into online travel, both in the United States and internationally. Meta-search services leverage their search technology to aggregate travel search results for the consumer's specific itinerary across travel service provider (e.g., accommodations, rental car companies or airlines), OTC and other travel websites and, in many instances, compete directly with us for customers. Meta-search services intend to appeal to consumers by showing broader travel search results than may be available through OTC or other travel websites, which could lead to travel service providers or others gaining a larger share of search traffic. TripAdvisor has begun

supporting its meta-search service with offline advertising, and trivago, a leading meta-search service in Europe, has been aggressively advertising in the United States since 2013. Through our KAYAK meta-search service, we compete directly with other meta-search services. KAYAK depends on access to information related to travel service pricing, schedules, availability and other related information from OTCs and travel service providers. To the extent OTCs or travel service providers do not provide such information to KAYAK, KAYAK's business and results of operations could be harmed.

Consumers may favor travel services offered by meta-search websites or search companies over OTCs, which could reduce traffic to our travel reservation websites, increase consumer awareness of our competitors' brands and websites and increase our advertising and other customer acquisition costs. To the extent any such consumer behavior leads to growth in our KAYAK meta-search business, such growth may not result in sufficient increases in profits from our KAYAK meta-search business to offset any related decrease in profits experienced by our travel service reservation brands. Further, meta-search services may evolve into more traditional OTCs by offering consumers the ability to make travel reservations directly through their websites. For example, TripAdvisor facilitates hotel reservations on its transaction websites Tingo and Jetsetter and, with respect to some accommodations, allows consumers to make a reservation while staying on TripAdvisor through its "Instant Booking" offering. Instant Booking now includes participation from six out of the top 10 global hotel brands, including Marriott International, Hyatt Hotels and Best Western International. We recently agreed to participate in "Instant Booking," and we do not yet know how this participation will affect our business. For example, while we expect to benefit from incremental business generated through "Instant Booking," participation could cannibalize business that would otherwise come to us through other ad offerings on TripAdvisor, directly (including after a consumer first visits TripAdvisor) or through other channels, some of which may be more profitable to us than reservations generated through "Instant Booking." Other meta-search providers may also offer direct booking services with travel service providers, which may lead to more consumers booking directly with a travel service provider rather than an OTC. For example, Google recently announced the discontinuation of its Hotel Finder meta-search service in favor of integrating hotels directly into search results and encouraging users to book hotel reservations directly through Google's "Book on Google" service, which it is now expanding from mobile phones to both desktops and tablets. To the extent consumers book travel services through a service such as Google's "Book on Google," a meta-search website or directly with a travel service provider after visiting a meta-search website or meta-search utility on a traditional search engine without using an OTC like us, or if meta-search services limit our participation within their search results or evolve into more traditional OTCs, we may need to increase our advertising or other customer acquisition costs to maintain or grow our reservation bookings and our business, gross bookings and results of operations could be adversely affected.

There has been a proliferation of new channels through which accommodation providers can offer reservations. For example, companies such as HomeAway (which is owned by Expedia) and Airbnb offer services providing vacation rental property owners, particularly individuals, an online place to list their accommodations where travelers can search and book such properties. Airbnb may also seek to compete directly with us by offering hotel and other accommodations through their online and mobile platforms. Further, meta-search services may lower the cost for new companies to enter the market by providing a distribution channel without the cost of promoting the new entrant's brand to drive consumers directly to its website. If any of these services are successful in attracting consumers who would otherwise use our services, our business and results of operations would be harmed.

Our OpenTable restaurant reservation business competes or may in the future compete with other restaurant reservation providers, such as LaFourchette (which is owned by TripAdvisor), Yelp's SeatMe service, Zomato, Bookatable (which is owned by Michelin), and Quandoo (which is owned by Recruit).

Companies offering new rental car business models and car- and ride-sharing services such as Uber, Lyft, Gett, BlaBlaCar and Zipcar (which is owned by Avis) provide alternative options for consumers considering renting a car. These companies extensively utilize mobile platforms and new technologies to drive demand for their services. If any of these services are successful in attracting consumers who would otherwise use priceline.com's or rentalcars.com's rental car reservation services, our business and results of operations could be harmed.

Travel service providers, including multi-national hotel chains, rental car companies and airlines with which we conduct business, compete with us in online channels to drive consumers to their own websites in lieu of third-party distributors such as us. Travel service providers may charge lower prices and, in some instances, offer advantages such as loyalty points or special discounts to members of closed user groups (such as loyalty program participants or customers with registered accounts), any of which could make their offerings more attractive to consumers than our services. Discounting may increase as competition authorities seek to allow increased pricing flexibility among providers of travel service reservations. We may need to offer similar advantages to maintain or grow our reservation bookings, which could adversely impact our profitability. Further, consolidation among travel service providers, such as Marriott International's acquisition of Starwood

Hotels & Resorts in November 2015, could result in lower rates of commission paid to OTCs, increased discounting, and greater incentives for consumers to join closed user groups as such groups expand their offerings.

Widespread adoption of mobile devices, such as the iPhone, Android-enabled smart phones and tablets such as the iPad, coupled with the improved web browsing functionality and development of thousands of useful "apps" available on these devices, is driving substantial online traffic and commerce to mobile platforms. We have experienced a significant shift of business to mobile platforms and our advertising partners are also seeing a rapid shift of traffic to mobile platforms. Our major competitors and certain new market entrants are offering mobile apps for travel products and other mobile functionality, including proprietary last-minute discounts for accommodation reservations. Advertising and distribution opportunities may be more limited on mobile devices given their smaller screen sizes. The gross profit earned on a mobile transaction may be less than a typical desktop transaction due to different consumer purchasing patterns. For example, accommodation reservations made on a mobile device typically are for shorter lengths of stay and are not made as far in advance. Further, given the device sizes and technical limitations of tablets and smart phones, mobile consumers may not be willing to download multiple apps from multiple companies providing a similar service and instead prefer to use one or a limited number of apps for their mobile travel and restaurant research and reservation activity. As a result, the consumer experience with mobile apps as well as brand recognition and loyalty are likely to become increasingly important. Our mobile offerings have received generally strong reviews and are driving a material and increasing share of our business. We believe that mobile bookings present an opportunity for growth and are necessary to maintain and grow our business as consumers increasingly turn to mobile devices instead of a personal computer and to mobile apps in addition to a web browser. If we are unable to continue to rapidly innovate and create new, user-friendly and differentiated mobile offerings and efficiently and effectively advertise and distribute on these platforms, or if our mobile apps are not downloaded and used by consumers, we could lose market share to existing competitors or new entrants and our future growth and results of operations could be adversely affected.

Apple, one of the most innovative and successful companies in the world and producer of, among other things, the iPhone and iPad, obtained a patent for "iTravel," a mobile app that would allow a traveler to check in for a travel reservation. In addition, Apple's iPhone operating system includes "Wallet" (formerly known as "Passbook"), a virtual wallet app that holds tickets, boarding passes, coupons and gift cards, and, along with iTravel, may be indicative of Apple's intent to enter the travel reservations business in some capacity. Apple has substantial market share in the smart phone category and controls integration of offerings, including travel services, into its mobile operating system. Apple also has more experience producing and developing mobile apps and has access to greater resources than we have. Apple may use or expand iTravel, Wallet, Siri (Apple's voice recognition "concierge" service), Apple Pay (Apple's mobile payment system) or another mobile app or functionality as a means of entering the travel reservations marketplace. Similarly, Google's Android operating system is the leading smart phone operating system in the world. As a result, Google could leverage its Android operating system to give its travel services a competitive advantage, either technically or with prominence on its Google Play app store or within its mobile search results. To the extent Apple or Google use their mobile operating systems or app distribution channels to favor their own travel service offerings, our business could be harmed.

Competition in U.S. online travel remains intense and online travel companies are creating new promotions and consumer value features in an effort to gain competitive advantages. In particular, the competition to provide "opaque" accommodation reservation services to consumers, an area in which our priceline.com business has been a leader, has become more intense. For example, Expedia makes opaque accommodation room reservations available through its Hotwire brand and on its principal website under the name "Expedia Unpublished Rates" and has, we believe, supported this initiative with steeper discounts through lower margins. We believe these offerings, in particular "Expedia Unpublished Rates," have adversely impacted the market share and year-over-year growth rate of priceline.com's Name Your Own Price® opaque hotel reservation service, which has been experiencing a decline in room night reservations since 2011. Competitors could also launch opaque rental car services, which could negatively impact priceline.com's opaque Name Your Own Price® rental car reservation service. If Expedia or others are successful in growing their opaque reservation services, we may have less consumer demand for our opaque reservation services over time, and we would face more competition for access to the limited supply of discounted reservation rates. As a result of this increased competition, our share of the discount accommodation reservation market in the United States could further decrease, which could harm our business and results of operations. In addition, high hotel occupancy levels in the United States have had an adverse impact on our access to hotel rooms for our opaque hotel reservation services. Further, growth in discounted closed user group retail prices for hotel rooms lessens the price difference for members of the closed user group between a retail hotel reservation and an opaque hotel reservation, which we believe has led to fewer consumers using our opaque hotel reservation services.

During 2015, Expedia acquired Travelocity, Orbitz and HomeAway. To the extent these acquisitions enhance Expedia's ability to compete with us, in particular in the United States, which is Expedia's, Travelocity's, Orbitz's and HomeAway's largest market, our market share, business and results of operations could be adversely affected.

Operations and Technology

Our business is supported by multiple systems platforms, which were designed with an emphasis on scalability, performance and reliability. The platforms are largely independent among Booking.com, priceline.com, KAYAK, agoda.com, rentalcars.com and OpenTable. The software platforms and architecture use a variety of tools within each corporate implementation, including server-side Java, C++, ASP, .Net, Perl, PHP, JavaScript and SQL scripts integrated with Oracle, MySQL, MongoDB, Cassandra and Microsoft SQL-server database systems. These internal platforms were designed to include open application protocol interfaces that can provide connectivity to vendors in the industries in which we operate. These include large global systems, such as accommodation, airline ticket and rental car reservation systems and financial service providers, as well as individual accommodation service providers, such as individual hotels. Our applications utilize digital certificates to help us conduct secure communications and transactions, as appropriate.

The systems infrastructure and web and database servers of our worldwide operations are primarily hosted in the United Kingdom, Switzerland, the Netherlands, Germany, Singapore, Hong Kong and four locations in the United States, each of which provides network connectivity, networking infrastructure, UPS conditioned power and 24-hour monitoring and engineering support typical of hosted data centers. All data center facilities have a continuous power supply system, generators, redundant servers and multiple back-up systems. Although we take steps to mitigate the effects of any loss or reduction in service at one of our hosting facilities, if a hosting facility were inaccessible or otherwise experienced a disruption in service for any reason, we could experience a disruption to our services, loss of transactions and revenue and consumer complaints.

Customer service for our international business is provided primarily through in-house call centers. We outsource most of the call center and customer service functions for our U.S. businesses.

Intellectual Property

Over time and through acquisitions, we have assembled a portfolio of patents, trademarks, service marks, copyrights, domain names, and trade secrets covering our services. We regard the protection of our intellectual property as critical to our success. We protect our intellectual property rights by relying on national, federal, state and common law rights in the United States and internationally, as well as a variety of administrative procedures, regulations, conventions and treaties. We also rely on contractual restrictions to protect our proprietary rights in our services. We enter into confidentiality and invention assignment agreements with employees and contractors and nondisclosure agreements with parties with whom we conduct business in order to limit access to and disclosure of our proprietary information.

We pursue the registration of our domain names, trademarks and service marks in the United States and internationally. We currently hold numerous issued U.S. and international patents and pending U.S. and international patent applications. We file additional patent applications on new inventions, as we deem appropriate. Effective trademark, copyright, patent, domain name, trade dress and trade secret protection is expensive to maintain and may require litigation. As we continue to expand internationally, protecting our intellectual property rights and other proprietary rights involves an increasing number of jurisdictions, a process that is expensive and time consuming and may not be successful in every location. See "Risk Factors - We face risks related to our intellectual property."

Governmental Regulation

The services we provide are subject to various laws and regulations. For example, our travel services are subject to laws governing the offer and/or sale of travel services as well as laws requiring us to register as a "seller of travel" in certain jurisdictions. In addition, our services may be subject to various taxing regulations. See "Risk Factors - We may have exposure to additional tax liabilities," "Risk Factors - Our financial results will likely be materially impacted by payment of income taxes in the future" and "Risk Factors - Adverse application of state and local tax laws could have an adverse effect on our business and results of operations."

We are subject to laws that require protection of user privacy and user data. In our processing of reservations, we receive and store a large volume of personally identifiable data in the United States, Europe and Asia. This data is increasingly subject to laws and regulations in numerous jurisdictions around the world. Such government action is typically intended to protect the privacy of personal data that is collected, processed and transmitted in or from the governing jurisdiction. See "Risk Factors - Our processing, storage, use and disclosure of personal data exposes us to risks of internal or external security breaches and could give rise to liabilities" and "Risk Factors - 'Cookie' laws could negatively impact the way we do business."

We are also subject to anti-trust and competition laws, and the competition authorities in various jurisdictions have begun investigations into competitive practices within the online travel industry, including with respect to our business. See "Risk Factors - As the size of our business grows, we may become increasingly subject to the scrutiny of anti-trust and competition regulators."

In addition, our strategy involves rapid geographic expansion around the world, including in Asia, South America and elsewhere, many of which regions and countries have different legislation, regulatory environments and tax laws. Compliance with legal, regulatory and tax requirements around the world places demands on our time and resources, and we may nonetheless experience unforeseen and potentially adverse legal, regulatory or tax consequences, which may have an adverse effect on our business. See "Risk Factors - We face risks related to the growth rate and expansion of our international business" and "Risk Factors - Regulatory and legal requirements and uncertainties could harm our business."

Seasonality

A meaningful amount of our gross bookings are generated early in the year, as customers plan and reserve their spring and summer vacations in Europe and North America. From a cost perspective, we expense the substantial majority of our advertising activities as the expense is incurred, which is typically in the quarter in which reservations are booked. However, we generally do not recognize associated revenue until future quarters when the travel occurs. As a result, we have historically experienced our highest levels of profitability in the second and third quarters of the year, which is when we experience the highest levels of accommodation checkouts for the year for our European and North American businesses. We experience the highest levels of booking and travel consumption for our Asia-Pacific and South American businesses in the first and fourth quarters. Therefore, if these businesses grow faster than our European and North American businesses, our operating results for the first and fourth quarters of the year may become more significant over time as a percentage of full-year operating results.

In addition, the date on which certain holidays fall can have an impact on our quarterly results. For example, in 2013 our second quarter year-over-year growth rates in revenue, gross profit, operating income and operating margins were adversely affected by Easter falling in the first quarter instead of the second quarter, as it did in 2012. Conversely, our second quarter 2014 year-over-year growth rates in revenue, gross profit, operating income and operating margins were favorably impacted by Easter falling in the second quarter instead of the first quarter, as it did in 2013. Similarly to 2013, in 2016 Easter will fall in the first quarter instead of the second quarter, and will therefore likely have a positive effect on our first quarter 2016 year-over-year growth rates and a negative effect on our second quarter 2016 year-over-year growth rates as compared to the same periods in 2015 when Easter fell in the second quarter.

The impact of seasonality can be exaggerated in the short term by the gross bookings growth rate of the business. For example, in periods where our gross bookings growth rate decelerates, such as the third quarter of 2015, our operating margins typically benefit from relatively less variable advertising expense. In addition, gross profit growth is typically less impacted in the near term due to the benefit of revenue related to reservations booked in previous quarters.

Employees

As of December 31, 2015, we employed approximately 15,500 employees, of which approximately 3,200 are based in the United States and approximately 12,300 are based outside the United States. We also retain independent contractors to support our customer service, website content translation and system support functions.

We have never had a work stoppage and we consider our relations with our employees to be good. Although we have works councils or employee representatives in certain countries, our U.S. employees are not represented by a labor union and are not covered by a collective bargaining agreement. Our future success will depend, in part, on our ability to continue to attract, integrate, retain and motivate highly qualified technical and managerial personnel, for whom competition is intense. See "Risk Factors - We rely on the performance of highly skilled personnel; and, if we are unable to retain or motivate key personnel or hire, retain and motivate qualified personnel, our business would be harmed."

The Priceline Group Websites

We maintain websites with the addresses www.pricelinegroup.com, www.booking.com, www.priceline.com, www.kayak.com, www.agoda.com, www.rentalcars.com and www.opentable.com, among others. We are not including the information contained on our websites as a part of, or incorporating it by reference into, this Annual Report on Form 10-K. We make available free of charge through the www.pricelinegroup.com website our Annual Reports on Form 10-K, Quarterly Reports on Form 10-Q and Current Reports on Form 8-K, and amendments to these reports filed or furnished pursuant to

Section 13(a) or 15(d) of the Securities Exchange Act of 1934, as amended (the "Exchange Act"), as soon as reasonably practicable after we electronically file such material with, or furnish such material to, the SEC. These reports and other information are also available, free of charge, at www.sec.gov. Alternatively, the public may read and copy any materials we file with the SEC at the SEC's Public Reference Room at 100 F Street, N.E., Washington, D.C. 20549. Information on the operation of the Public Reference Room may be obtained by calling the SEC at 1-800-SEC-0330. In addition, the Company's Code of Conduct is available through the www.pricelinegroup.com website and any amendments to or waivers of the Code of Conduct will be disclosed on that website.