Updated 4:50 p.m. ET

Sears Holdings (SHLD) has been an oddball stock for a long time, but this January it's just gone bonkers.

Look at what's happened in the last trading day. Shares shot up more than 10% Monday in morning trading, and finally fell back to a 3.3% loss to close at $47.39. Why? No one knows. But this action is just a normal trading day with Sears. Shares are up more than 50% so far this year.

The thing is, there's nothing going on with the company itself to justify such a rally. Sears is in the middle of closing down more than 100 stores, and the company's own financials show little investment in its future. Some suppliers aren't getting paid. The credit rating has been downgraded. Cash is dwindling.

So you get the real sense that there are other plays at work here. Manipulation. Investors trading on fear and opportunity. Short covering.

One analyst explains why she sees a short squeeze in the stock in the following video.

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It all revolves around Chairman Eddie Lampert, who already owns about 60% of the company. He's been on a massive shopping binge for Sears shares, personally buying $159 million in stock this month from his own hedge firm. Sears has been buying back huge amounts of its own shares for years, reducing the float for everyone else.

Lampert's actions helped ignite a rumor that the company might get taken private.

Finally, you have to consider that Sears might be in what The Wall Street Journal suggests is "the mother of all short squeezes." There are very few shares to short, and Sears shares are among the most expensive to borrow, the Journal reported. Short sellers borrow shares and sell them, hoping that the stock price drops enough that they can buy back the shares at a lower price and return them.

If the stock price doesn't drop -- as we're seeing with Sears this month -- some short sellers just buy back the shares and get out. And then the stock price climbs a little more.

"You gotta get out of the way of this thing now," a hedge fund manager with Rosecliff Capital told CNBC. Lampert will "do anything to keep the run going, even sell the company."

Goldman Sachs (GS) really wants this run to continue. The Journal reported that Goldman's clients invested $3.5 billion in Lampert's hedge fund about four years ago. But after Sears shares fell 57% last year, the fund -- and the Goldman investment -- has taken a huge hit.

But Goldman's clients can't withdraw their money until the end of this year, the Journal reports, so the firm is extremely interested in keeping the stock price high. Just a little added pressure on Lampert there.

Related reading:

• Sears lists the stores it will close

• Bruce Berkowitz: Tears for Sears?

• The number to pay attention to at Sears