• by Mark Walsh  @markfwal, March 29, 2012

Mobile ad network Millennial Media made a strong debut Thursday on the New York Stock Exchange, with its stock price nearly doubling to $25 a share at the opening. The company priced its shares Wednesday night at $13 each, at the high end of the $11 to $13 range. Earlier this month, Millennial had set a range of $9 to $11.

The company’s hot start in the market reflects optimism about the growth of Millennial’s business and mobile advertising more widely. Millennial doubled its revenue to $106 million in 2011 but remains unprofitable as of the fourth quarter of last year. eMarketer has predicted U.S. mobile ad spending overall will jump 80% this year to $2.6 billion.

Investor enthusiasm for Millennial also reflects a rebounding IPO market. Shares of organic food company Annie’s on Wednesday rose 89% on its first day of trading, making it the best-performing IPO since LinkedIn went public Last May.