MGL Asset Management Group's press release purporting to offer $7.25 per share for Krispy Kreme Doughnuts (NYSE: KKD) was pretty quickly debunked as illegitimate and, very probably, an effort to hype the stock for a quick buck. Jon Ogg reported on the mysterious offer on our sister site, BloggingBuyouts.

The stock jumped on the news of the offer, but quickly gave up all the gains and then some after media and analyst reports dismissed the offer. But anyone who jumped on the stock at the sight of the press release got burned.

How can you prevent this from happening to you? A good rule of thumb: When you're looking for information on material developments, look to the SEC filings. The offer was made solely through a press release -- something that anyone with a few hundred bucks to pay the wire fee could send into the hands of millions of investors in a few minutes. Until you see something about the "offer" in the SEC's Edgar Database, it should be regarded as a rumor. I wrote about a similarly non-materializing offer at Trans World Entertainment (NASDAQ: TWMC) back in November.

Another solution is to leave the "in-play" trading to the pros -- it's all about information and you're unlikely to have an edge. If you see a news item that a company has received an offer, don't jump in.