Item 1A. Risk Factors

There have been no material changes from the risk factors identified under the heading "Risk Factors" in our Annual Report on Form 10-K for the year ended December 31, 2020.

Item 2. Unregistered Sales of Equity Securities and Use of Proceeds

During the three months ended September 30, 2021, we acquired shares of our common stock held by employees who tendered shares to satisfy tax withholding obligations upon the vesting of previously issued restricted stock awards. Specifically, the number of shares of common stock acquired from employees and the average prices paid per share for each month in the third quarter ended September 30, 2021 are as shown in the table below.

On May 1, 2020, our Board of Directors authorized a share repurchase program whereby we may repurchase up to $1 billion of common stock through December 31, 2021 (the "Repurchase Program"). Under this authorization, we are not required to purchase shares but may choose to do so in the open market or through private transactions at times and amounts based on our evaluation of market conditions and other factors. We expect to finance any share repurchases under the Repurchase Program using available cash and may use proceeds from borrowings or debt offerings. We did not repurchase any shares of our common stock during the three months ended September 30, 2021.