Red Hat Inc (RHT.N), the world's largest commercial distributor of the Linux operating system, reported lower-than-expected fourth-quarter revenue, sending its shares down 11 percent after markets closed.
Net income rose to $43 million, or 22 cents per share, in the fourth quarter, from $36 million, or 18 cents per share, a year earlier.
Excluding items, the company earned 36 cents per share.
Revenue rose 17 percent to $348 million.
Analysts on average expected adjusted earnings of 30 cents per share, on revenue of $350 million, according to Thomson Reuters I/B/E/S.
"We see institutional buyers backing off without really giving a clear reason why," Cross Research analyst Richard Williams said.
Red Hat's Linux operating system is a major competitor to Microsoft Corp's (MSFT.O) Windows in corporate markets, especially on servers.
Shares of the company were trading at $44.45 after closing at $49.97 on the New York Stock Exchange on Wednesday.
(Reporting by Neha Alawadhi and Aditya Kondalamahanty in Bangalore; Editing by Joyjeet Das)