Monday is the only business day in the week that has historically come out a loser for the stock market, with the Dow finishing down 52 percent of the time over the past 84 years.

The Dow's been down 11 of the past 12 Mondays.

Mercer County stock expert Ken Kamen says he's not sure this has a lot of relevance for investors. He speculates that perhaps over the weekend you get a chance to reflect on your investments and do a little bit of home work. And come Monday morning, he says you come in and maybe you continue that homework with some data searching and then you're ready to invest by Tuesday.

Taking a positive spin, Kamen says, because stocks are going to be down historically on Mondays - you would rather buy them cheaper than expensive. So Monday seems as good a time as any.

He says, "If you're going to average into the market over time, you might as well make Monday your day to purchase stock."

But Kamen adds, "Everyone kind of shakes their head that we keep climbing this, "wall of worry", and then they have the weekend to reflect on that and they say, 'okay, this might be the week in which things aren't going to go well and they take Monday off, so to speak."

The theory is also advanced that sometimes, when a company has bad news to disseminate, they hold off release till after the market closes on Friday evening. And the fallout from the news hits Wall Street on....Monday.