Basic net income per common share is based on the weighted average number of common shares outstanding and the weighted average minimum number of shares issued upon settlement of the stock purchase contracts issued under the tangible equity units. Diluted net income per common share is based on the weighted average number of common shares outstanding and potentially dilutive shares. The dilutive effect of employee stock-based compensation is included in the computation of diluted net income per common share. The dilutive effect of stock-based compensation is calculated using the treasury stock method and expected proceeds upon exercise of the stock-based compensation. The treasury stock method assumes that the proceeds from stock-based compensation is used to purchase the Company’s common stock at the average market price during the period. The following table summarizes the shares, in thousands, used in computing basic and diluted net income per common share: