Warning that it remains cautious about the economy, Activision Blizzard Inc. late Wednesday reported a larger fourth quarter loss after taking changes that included reducing the value of its music and other “casual” video game titles.

The Santa Monica company, better known for its hard-core gamer “Call of Duty” and “World of Warcraft” franchises said it lost $286 million (-23 cents per share), compared with a net loss of $72 million (5 cents) a year earlier. Net revenue fell 5 percent to $1.56 billion.

Excluding one-time items, the company earned $632 million (49 cents), up 47 percent from a year earlier. Adjusted revenue was $2.5 billion. Analysts surveyed by Thomson Reuters in average expected adjusted per-share earnings of 43 cents on revenue of $2.23 billion.

“On a non-GAAP basis, our performance enabled us to deliver the most profitable year in our company’s history,” said Chief Executive Robert Kotick in a press release.

For 2010, Activision forecast adjusted earnings of 70 cents per share on sales of $4.4 billion. Analysts are expecting 73 cents per share earnings on revenue of $4.8 billion.

But the company added that it plans buy back up to $1 billion of its stock and on Apriol 2 will pay its first annual dividend, equal to 15 cents per share, to shareholders of record as of February 22.

Activision shares earlier closed up 5 cents, or less than1 percent, to $10.10 on the Nasdaq and rose 6 percent in after-hours trading.