Feb 17 (Reuters) - Warren Buffett said Berkshire Hathaway Inc's recent investment in Activision Blizzard Inc has been "no bonanza" for Berkshire, and was made without knowing the video game maker would receive a takeover offer from Microsoft Corp.

In a letter released by Buffett's office on Thursday, Buffett said one of his investment managers paid about $77 per share for Berkshire's 14.7 million Activision shares, acquiring about 85% of his position in October and the rest in November.

Buffett also said Berkshire had "no prior knowledge" that Microsoft was working on a $68.7 billion takeover of Activision, whose franchises include "Call of Duty" and "Candy Crush," announced on Jan. 18.

He did not say which investment manager, Todd Combs or Ted Weschler, made Berkshire's approximately $1.1 billion investment.

Buffett sent his letter to various media that had reported on the investment, after one incorrectly said Berkshire paid an average of $66.53 per share for its Activision stake, not $77.

That report was later corrected.

Buffett said his investment manager could have amassed his stake after the merger was announced, when Activision sometimes traded at around $78 per share. "His purchase was no bonanza of any sort for him or Berkshire," Buffett wrote.

Activision shares fell in November amid accusations concerning sexual harassment of employees and misconduct by several top managers.

The shares closed Thursday down 49 cents at $80.97, below Microsoft's $95 per share takeover offer. Analysts expect the merger will get tough antitrust scrutiny.

Berkshire Vice Chairman Charlie Munger on Wednesday called Activision chief Bobby Kotick "one of the smartest business executives I know."

Munger spoke at the annual meeting of Daily Journal Corp , the newspaper publisher and legal software company he chairs. (Reporting by Jonathan Stempel in New York Editing by Chris Reese)