This excerpt taken from the UNH 10-K filed Feb 11, 2009.
Employee Stock Purchase Plan
The Companys Employee Stock Purchase Plan (ESPP) is intended to enhance employee commitment to the goals of the Company, by providing a means of achieving stock ownership at advantageous terms to eligible employees of the Company. Eligible employees are allowed to purchase the Companys stock at a discounted price, which is 85% of the lower market price of the Companys common stock at the beginning or at the end of the six-month purchase period. During 2008, 2007 and 2006, 2.9 million shares, 1.9 million shares and 1.9 million shares of common stock, respectively, were purchased under the ESPP. The compensation expense is included in the compensation expense amounts recognized and discussed below. At December 31, 2008, there were 13.1 million shares of common stock available for issuance under the ESPP.