Millennial Media Inc., a Baltimore-based mobile advertising firm, posted its first quarterly results as a public company Monday. The results included a $4 million loss but were in line with Wall Street's expectations.

The company reported revenues of $32.9 million — more than 50 percent more in the first quarter this year than the $21.5 million it had in the similar period last year. Analysts estimated that Millennial would post revenue of $34.2 million, according to analysts surveyed by Bloomberg.

Millennial's $4 million loss was about 5 cents a share, which analysts expected, according to Bloomberg. In the first quarter last year, the company posted a loss of $23,000.

Millennial officials have said they planned to use the capital raised by the company's initial public offering — more than $130 million on March 29 — to expand business overseas and invest in new technologies. The company said its ad network can reach 300 million cellphone and smartphone users worldwide, including 140 million in the United States.

"Our mission at Millennial Media is to power the app economy through mobile advertising," said Paul Palmieri, Millennial's co-founder, president and chief executive officer, during a conference call with analysts Monday. "The app economy is in the very early stages of evolution, and we don't take our leadership position lightly."

Shares of Millennial ended trading Monday at $15.45, before the quarterly financial results were released at the close of markets. Millennial has a market capitalization of $1.16 billion.

Millennial makes money by charging advertisers who wish to reach a mobile audience with small ads displayed on consumers' smartphones. Mobile application developers join Millennial's ad network and agree to allow the advertisements to appear in their apps; they make money from Millennial when users click on the mobile ads.

Millennial's strategy is to attract application developers and encourage them to join Millennial's network. The company also works with major brands and advertisers, who are urged to spend an increasing chunk of their marketing dollars with Millennial.

Millennial's biggest competitors are Google and Apple, which both offer mobile ad services to app publishers and marketers.

Millennial and other companies have predicted a tsunami of spending on mobile advertising in the coming years.

In its IPO registration filing, Millennial cited industry data that showed the worldwide mobile ad market would grow from $1.8 billion last year to $13.5 billion in 2015. And mobile app downloads — on smartphone platforms such as Apple's iPhone and Google's Android handsets — are expected to mushroom from 17.7 billion last year to 108.8 billion in 2015.

Palmieri said the company's international reach has expanded over the past year. Millennial is able to sell mobile ads from the United States that run in other parts of the world.

The overseas activity has given Millennial's executives more insight into new markets and is helping guide the company in deciding where to open offices, Palmieri said.

Millennial's revenue from international customers climbed to $4 million in the first quarter, compared to $1.3 million in last year's first quarter, accounting for 12 percent of the company's total revenue, company officials said. Much of the growth came from the firm's European operations.

For the upcoming quarter, Millennial forecast that its revenues would be in the range of $37 million to $38 million, with a loss of $3.2 million to $3.5 million. Officials estimated full-year revenue for 2012 at between $173 million and $176 million, with a total loss in the range of $3 million to $4 million.