That the world is getting smaller has been illustrated by the relentless pace of mergers of the world's exchanges. National borders or products hardly matter—giving investors a broad, sophisticated electronic platform to trade as quickly and as cheaply as possible is all that counts.

The latest chapter is the news that the New York Mercantile Exchange, known primarily for its oil market, is in talks to be acquired by the Chicago Mercantile Exchange, once a largely agricultural market, for $11 billion.

The talks are in "early stages," the companies said in a statement. Under the terms being discussed, shareholders of Nymex would receive $36 in cash and a 0.1323 share of CME Group, the parent of the Chicago Merc, for each of their shares.

A deal would be the latest in a wave of exchange mergers in the last two years. C.M.E. acquired the Chicago Board of Trade for $12 billion last year to create the world's largest exchange for derivatives trading. A Nymex rival in energy, the Intercontinental Exchange, has merged with the New York Board of Trade. And the New York Stock Exchange acquired Euronext, while the Nasdaq market sought unsuccessfully to win the London Stock Exchange.

An acquisition by the Chicago Merc could push Nymex into new products, but would keep the exchange's Manhattan trading floors.

The two exchanges already have a 10-year deal that allows for Nymex crude oil contracts to trade electronically on the Chicago Merc's platform.

"Nymex is probably not big enough to survive as an island in this ongoing consolidation of exchanges," William Cline, former managing partner of the consulting company Accenture Ltd., told Bloomberg News. "For the C.M.E., it's a natural extension to move more into energy products."

Dwight Cass and Cyrus Sanati of Breakingviews.com say that the offer comes at the right time for Nymex, as the exchange typically has the most trading volume when energy prices are rising. With signs that the U.S. economy may be sliding into a recession, energy trading could slow.

For the Chicago Merc, Nymex "would round out C.M.E.'s product line nicely," they say. "Antitrust worries are minimal, since the two companies have little overlap."
 
 
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