Shares of Marsh & McLennan Cos. had their biggest gain in six months on Tuesday as speculation increased that the company may be a takeover target.

The stock rose 3.2%, to $31.35 from its opening on Tuesday until midday on Wednesday. On Tuesday, 8.8 million shares of of the New York company were traded, which was more than triple the three-month daily average as the stock rose 3.7%.

Christine Walton, a spokeswoman for New York-based Marsh & McLennan, told Bloomberg that it is her company’s policy not to comment on market rumors.

Trading in options to buy the shares surged more than twelvefold. The number of call-option contracts traded jumped to 28,319 from 2,216, the average of the previous 20 days, according to Bloomberg’s data.

Analysts said they are waiting for the other shoe to drop following the announcement Monday of a leveraged buyout of student loan company SLM Corp., which is better known as Sallie Mae.

Sallie Mae announced Monday it accepted a $25 billion takeover bid from a group of investors.

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