CBOE rallied as much as 5.1 percent as investors speculated the owner of the Chicago Board Options Exchange is dropping its opposition to a merger. Chairman and Chief Executive Officer William Brodsky said in a July 26 interview that the company had no need for a deal.

Bets that CBOE may be purchased follow Frankfurt-based Deutsche Boerse AG’s Feb. 15 agreement to buy New York-based NYSE Euronext for $9.53 billion, creating the world’s largest exchange operator. Singapore Exchange Ltd. bid A$8.35 billion ($8.47 billion) in October for ASX Ltd., which runs the Australian stock market, and London Stock Exchange Group agreed Feb. 9 to pay 1.94 billion pounds ($3.15 billion) to buy Canada’s TMX Group Inc.

“As exchanges look to diversify and grow in derivatives, CBOE is a natural target,” said Rich Repetto, a New York-based analyst at Sandler O’Neill & Partners LP who rates the stock at “hold.” “They’re a major player in options and often looked at as a consolidation candidate because they focus only on options and they control some very important indexes and proprietary products.”

Gail Osten, a spokeswoman for CBOE, declined to comment.

CBOE rose 3.1 percent to $26.78 at 3 p.m. New York time. The shares have risen 9.4 percent since Feb. 9, when Deutsche Boerse said it was negotiating to acquire NYSE Euronext.

CBOE has the exclusive right to trade options on the U.S. equity benchmark. S&P 500 options volume of 175 million contracts last year was the third-largest among all stocks and indexes and accounted for 4.5 percent of U.S. transactions, according to the Options Clearing Corp.