SAN FRANCISCO — Investors will likely focus on Facebook's mobile advertising revenue when the world's largest social media company reports second-quarter earnings after the stock market closes Wednesday.

So far, Facebook Inc. shown it can grow mobile ad revenue since it started showing people ads on their smartphones and other mobile gadgets. The company said nearly a third of its advertising revenue came from mobile in the first three months of the year, helping to push total revenue up 38 percent to $1.46 billion, from $1.06 billion.

Cantor Fitzgerald analyst Youssef Squali thinks mobile growth "should continue unabated," accounting for about 34 percent of total advertising revenue in the second quarter, up from 30 percent in the first. But he warned that a weaker ad market in Europe could hurt Facebook's international revenue. More than have of the nations that use the euro are now in recession and sales of almost everything, from cars to beer and cosmetics, are hurting.

Analysts, on average, are expecting earnings of 14 cents per share on revenue of $1.62 billion, according to a poll by FactSet. Facebook , based in Menlo Park, Calif., has not provided earnings or revenue guidance for the quarter.

Even a strong earnings report is unlikely to propel Facebook's stock above its $35 initial public offering price from more than a year ago. As of Tuesday's closing at $26.13, the company's stock is down by 25 percent from the IPO price.