Item 5. MARKET FOR REGISTRANT’S COMMON EQUITY, RELATED STOCKHOLDER MATTERS AND ISSUER PURCHASES OF EQUITY SECURITIES.

Our common stock is traded on the New York Stock Exchange under the symbol “TYL.” At December 31, 2018, we had approximately 1,262 stockholders of record. Most of our stockholders hold their shares in street name; therefore, there are substantially more than 1,262 beneficial owners of our common stock.

We did not pay any cash dividends in 2018 or 2017. Our bank credit agreement contains restrictions on the payment of cash dividends. We intend to retain earnings for use in the operation and expansion of our business and do not anticipate paying a cash dividend in the foreseeable future.

The following table summarizes certain information related to our stock incentive plan, restricted stock units and our employee stock purchase plan. There are no warrants or rights related to our equity compensation plans as of December 31, 2018.

(a) In May 2018, stockholders approved our 2018 Stock Incentive Plan ("the 2018 Plan") which amended and restated the existing Tyler Technologies, Inc. 2010 Stock Option Plan ("the 2010 Plan"). Upon stockholder approval of the 2018 Plan, the remaining shares available for grant under the 2010 Plan were added to the shares authorized for grant under the 2018 Plan. Additionally, any awards previously granted under the 2010 Plan that expire unexercised or are forfeited are added to the shares authorized for grant under the 2018 Plan. Under the 2018 Plan, each award granted, other than stock options, reduces the number of securities available for issuance under the 2018 Plan by 2.5 shares.

As of December 31, 2018, we had authorization to repurchase up to approximately 1.2 million additional shares of Tyler common stock. During 2018, we purchased approximately 781,000 shares of our common stock for an aggregate purchase price of $150.1 million. A summary of the repurchase activity during 2018 is as follows:

The repurchase program, which was approved by our board of directors, was announced in October 2002 and was amended at various times from 2003 through 2019. There is no expiration date specified for the authorization, and we intend to repurchase stock under the program from time to time.

Subsequent to December 31, 2018, our board of directors authorized the repurchase of an additional 1.5 million shares of Tyler common stock. As of February 20, 2019, we had remaining authorization to repurchase up to 2.7 million additional shares of our common stock.

Performance Graph

The following Performance Graph and related information shall not be deemed “soliciting material” or to be “filed” with the Securities and Exchange Commission, nor shall such information be incorporated by reference into any future filing under the Securities Act of 1933 or Securities Exchange Act of 1934, each as amended, except to the extent that we specifically incorporate it by reference into such filing.

The following table compares total shareholder returns for Tyler over the last five years to the Standard and Poor’s 500 Stock Index and the Standard and Poor’s 600 Information Technology Index assuming a $100 investment made on December 31, 2013. Each of the three measures of cumulative total return assumes reinvestment of dividends. The stock performance shown on the graph below is not necessarily indicative of future price performance.