Berkshire Hathaway has a 9.5% stake in Activision Blizzard, billionaire Warren Buffett revealed on Saturday at Berkshire's annual meeting.

The big picture: Berkshire has been buying shares of the video game giant since January, when it bought stock just before Microsoft announced it had agreed to buy Activision for $68.7 billion in cash.

• Berkshire initially owned 2% in Activision before its latest purchases.

What they're saying: Buffett said the Activision stock purchases were his decision and a bet that the deal with Microsoft would close.

• "If the deal goes through, we make some money," Buffett said at Berkshire's annual shareholder meeting.