CHICAGO – In a move that underscores the wrenching global consolidation under way among commercial exchanges, Chicago Mercantile Exchange Holdings Inc. announced Tuesday that it will acquire crosstown rival CBOT Holdings Inc. for $8 billion in stock and cash.

The two companies said they expect to move to a single trading location at the CBOT, and the combined company will be renamed CME Group Inc.

The combination of the nation’s two largest futures exchanges comes at a time when trading of futures in agricultural commodities, foreign exchange, bonds and other financial instruments has surged, and when technological advances have made global futures trading a reality.

The trend has driven huge profits at exchanges in recent years, but it has also fostered a round of friendly and less-than-friendly acquisitions worldwide, as once-strictly-local exchanges seek to best position themselves for the challenges of the worldwide competition.

“Growth in the global derivatives industry is accelerating and new competitors are emerging in exchange, over-the-counter and other unregulated markets,” said CME Chief Executive Craig Donohue. The combined company “will be better positioned to capitalize on these trends and compete more effectively as our industry continues to transform,” he added.

Acquisition of the CBOT will create “one of the world’s most liquid marketplaces,” CME and its acquisition target said, and efficiencies created by the combination will yield annual savings of $125 million.

At current prices, the combined company will be valued in the stock market at a whopping $25 billion.

Terms of the deal call for CBOT holders to exchange each of their shares for 0.3006 shares of CME Class A common, which at Monday’s night’s closing price would yield CBOT holders $151.28 a share. Holders will be able to opt for a like amount in cash rather than stock, but CME is limiting the total cash payout in the $8 billion deal to $3 billion.

“The idea to merge these two great companies has been contemplated for decades,” said CME Chairman Terrence Duffy. Executives said talks regarding a merger have been under way for nearly a year and in fact predated CBOT’s initial public offering last year.

But while the deal will make the CME a stronger competitor as it fights for business with the likes of international players such as the Eurex and the InterContinentalExchange, it also represents a combination of two markets with a long history of rivalry that at times has edged toward open hostility.

But Tuesday, as Wall Street showed its enthusiasm for the deal by bidding up the shares of both CME and CBOT, such concerns were put on the back burner.

“Both the CBOT and CME will flourish,” predicted Bob Knox, a clerk at the clearing firm of Henning-Carey LLC. Asked about the longtime rivalry between the two exchanges, Knox said, “Let bygones be bygones. This is a happy day.”