* Q4 adj earnings $0.39/share vs est $0.37
* Q4 rev rises 15 pct to $400.4 mln
* Sees 2015 adj earnings $1.54-$1.56/share
* Sees 2015 rev $1.73-$1.755 bln vs est $1.76 bln
(Adds forecast; updates shares)
March 27 (Reuters) - Red Hat Inc reported better-than-expected quarterly results, helped by strong subscription growth for its Linux operating system, but forecast full-year adjusted profit below average analyst estimate.
Shares of the company, which rose as much as 4 percent in extended trading on the results, were down about 1 percent after the company said it expected adjusted earnings of $1.54-$1.56 per share for the year started March 1.
Analysts on average were expecting $1.63 per share, according to Thomson Reuters I/B/E/S.
Red Hat also said on a call with analysts that it expected full-year revenue to rise 14 percent to $1.73-$1.755 billion, compared with average estimate of $1.76 billion.
The company said foreign exchange rate fluctuations and higher U.S. tax rate would affect its profit.
Red Hat forecast adjusted operating margin of 23.5 percent, down from 24.5 percent in 2014, as it expects to invest more in its OpenStack and other technologies.
For the first quarter, the company said it expected an adjusted profit of 32-33 cents per share on revenue of $412-$415 million. Analysts were expecting a profit of 38 cents per share on revenue of $415.9 million.
Red Hat's Linux competes with Microsoft Corp's Windows operating systems in corporate markets, especially for use in servers.
Linux servers are in demand as more companies use the operating system in their cloud infrastructure. Red Hat's customers include Amazon Inc, Dell Inc, Alcatel Lucent SA.
Linux hardware revenue rose 14.4 percent to $4.1 billion in the fourth quarter of 2013 and share of Linux servers rose 4.6 points to represent 28.5 percent of all server revenue, according to IDC research. (http://r.reuters.com/huh97v)
Red Hat's net income rose to $45.07 million, or 24 cents per share, for the quarter ended Feb. 28, from $42.97 million, or 22 cents per share, a year earlier.
"The fourth quarter was ... highlighted by a record number of deals over $1 million and 24 percent growth in our billings proxy to $565 million," Chief Executive Jim Whitehurst said in a statement.
Billings proxy is defined by the company as total revenue plus change in deferred revenue.
On an adjusted basis, the company earned 39 cents per share, above analysts' consensus estimates of 37 cents per share.
Revenue rose 15 percent to $400.4 million.
Subscription revenue rose to $351 million.
Analysts had expected revenue of $398.9 million, according to Thomson Reuters I/B/E/S.
Shares of the company have gained 14 percent over the last year up to Thursday's close of $56.13.
(Reporting by Soham Chatterjee; Editing by Don Sebastian)