SHAREHOLDERS' EQUITY

Basic and diluted income per share was determined based on the following share data (in thousands):



	Three Months Ended September 30,		Nine Months Ended September 30,
	2018	2017	2018	2017
Weighted average basic common shares	12,799	11,999	12,437	11,931
Effect of stock options	758	1,619	1,160	1,598
Effect of dilutive share awards	110	101	167	96
Effect of Convertible Senior Notes and warrants	183	55	535	—
Weighted average diluted common shares	13,850	13,774	14,299	13,625

For the three months ended September 30, 2018, the weighted average shares that were anti-dilutive, and therefore excluded from the calculation of diluted income per share, included options to purchase 0.5 million shares of common stock and 0.1 million restricted stock units. For the nine months ended September 30, 2018, the weighted average shares that were anti-dilutive included options to purchase 0.4 million shares of common stock.

For the three months ended September 30, 2017, the weighted average shares that were anti-dilutive, and therefore excluded from the calculation of diluted income per share, included options to purchase 0.3 million shares of common stock and 0.1 million restricted stock awards. For the nine months ended September 30, 2017, the weighted average shares that were anti-dilutive included options to purchase 0.1 million shares of common stock.

The 0.625% Convertible Senior Notes due June 1, 2022 and the warrants issued by the Company in the second quarter of 2017 could be converted into the Company’s common stock in the future, subject to certain contingencies. See Note 11—Debt for additional information.

Shares of the Company's common stock associated with the warrants were excluded from the calculation of diluted income per share for the three months ended September 30, 2018 and 2017 as they were anti-dilutive since the strike price of the warrants was greater than the average market price of the Company's common stock during the respective periods. Shares of the Company’s common stock associated with the Convertible Senior Notes and the warrants were excluded from the calculation of diluted income per share for the nine months ended September 30, 2017, as they were anti-dilutive since the conversion price of the Convertible Senior Notes and the strike price of the warrants were greater than the average market price of the Company’s common stock during the period.

Common Stock Repurchases

In each of January 2010, May 2014, January 2016, February 2016 and February 2018, the board of directors authorized and the Company announced the repurchase of up to $10.0 million, $10.0 million, $50.0 million, $40.0 million and $100.0 million, respectively, of LendingTree's common stock. Pursuant to this stock repurchase program, the Company purchased 205,310 shares of its common stock for $57.2 million during the nine months ended September 30, 2018, and purchased 42,153 shares of its common stock for $10.0 million during the nine months ended September 30, 2017. At September 30, 2018, approximately $70.6 million of the previous authorizations to repurchase common stock remain available for the Company to purchase its common stock.