CHICAGO (AP) -- Candy maker Mars Incorporated is buying Chicago-based Wrigley Company in an all-cash deal valued at nearly $22 billion.

Under the agreement announced today, Wrigley's shareholders would receive $80 in cash for each share of common stock and Class B common stock.

After the buyout is completed in six to 12 months, Wrigley would become a subsidiary of Virginia-based Mars.

As of mid-January Wrigley has 217.5 million common shares outstanding as well as its 56.4 million Class B shares outstanding. That makes the deal valued at $21.9 billion.

The companies say the transaction is valued at $23 billion.

Warren Buffett's Berkshire Hathaway is making a minority equity investment in the new Wrigley subsidiary.