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McDonald's jumps in one of its biggest rallies in past five years

A McDonald's restaurant is pictured in Encinitas, California in this file photo from September 9, 2014. McDonald's Corp said February 9, 2015 its worldwide same-restaurant sales fell a steeper-than-expected 1.8 percent in January, as the company struggles to shake off the after-effects of food scandals in China and Japan. REUTERS/Mike Blake/Files (UNITED STATES - Tags: BUSINESS FOOD)

McDonald's (MCD) stock had an unusually strong session Wednesday -- but it wasn't immediately clear what sparked the run.

The shares closed up 3.9% at $98.66, and at its high for the day of $99.31, the stock had risen 4.6% from Tuesday. Volume was considerably higher than normal as well, with almost 16 million shares traded. On an average day, 7.2 million McDonald's shares trade hands, according to Yahoo Finance data. At the same time, CNBC's Dominic Chu, commenting on Twitter, noted heavy volume in McDonald's call options, a bet the stock will advance.

Here's how rare it is for the Golden Arches to see a change of this level: FactSet data show that, in the last five years, McDonald's has had only two days in which it advanced more. The biggest gain, almost 5.1%, was this past January after the company announced that Don Thompson would retire as CEO and be replaced by Steve Easterbrook on March 1. But because that information has been known for weeks, it generally wouldn't be leading to such trading activity on its own.

The only obvious news in fact wasn't particularly positive -- that activists want European regulators to investigate the manner in which Oak Brook, Ill.-based McDonald's pays its taxes.

What about the perhaps less-obvious? One reason is entirely plausible, and it's involving the dividend. Right now, McDonald's yields 3.6%. The stock starts trading ex-dividend Thursday, so anyone who bought shares today can be assured of getting the 85-cent payout scheduled for March 16. The dividend, which McDonald's raises every year, has long been one of the key attributes that's made the stock popular with investors.

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In this case, it might have to do. One restaurant industry analyst contacted for comment wasn't aware of any noteworthy developments. Another analyst who follows retail and restaurants thought at least part of the climb may have to do with McDonald's further discussing its plans to open and remodel fewer U.S. restaurants this year vs. last year, as described in the Chicago Tribune. That article cited information from McDonald's 10-K regulatory filing, released Tuesday, that it would open around 125 stores and refresh another 100 in 2015.

Still, McDonald's already had said in January, after it reported its most recent earnings, that it planned capital spending of around $2 billion this year. That would be the lowest level in more than five years, as construction is reduced in markets where sales have been weaker, including the U.S. It reiterated the $2 billion amount in the 10-K.

Other than those possibilities, the move suggested a new rumor of some type could be making its way to trading desks. Potentially, there again might be talk in the market of activists emerging in the months ahead. But that's speculation entirely. While certain investors with activist histories do own McDonald's shares today and have added to their holdings recently, the only known information there is almost two weeks old.

McDonald's hasn't yet responded to a request for comment. However, companies often have a policy or preference not to discuss stock-price movements.