Question: We own some 3M stock (ticker: MMM). It has steadily been over $100/share for several months. Do you know what we can expect as far as it splitting? Who or what causes it to split?

-- Kris Anderson, Lino Lakes, Minn.

Answer: Usually, a stock split occurs when a company wants to lower the price of its stock to make it more affordable for the average investor to buy. A split often occurs when a company's stock has reached a new high, so the company is usually believed to be on the upswing.

But remember that the value of the stock doesn't change. For instance, let's say you own 50 shares of a stock trading at $100, so that the value of your position is $5,000. The company decides to split the stock 2 for 1 -- the most common split. This means that the stock would now be worth $50 (half of the original price) but the number of shares you hold would double to 100. So, you end up with the same total value of $5,000.

Here you can see that Ford split its stock six times since it was issued.

• May 31, 1962 -- 2 for 1
• May 24, 1977 -- 5 for 4
• Dec. 1, 1983 -- 3 for 2
• Jun. 2, 1986 -- 3 for 2
• Jan. 12, 1988 -- 2 for 1
• Jul. 5, 1994 -- 2 for 1

Often, the price of a stock will rise just before an actual split. Some investors try to profit on splits by anticipating when they will occur although no one knows for sure until the company makes an official announcement.

You can check stock split calendars at a number of sites, including StockSplits.Net and the Motley Fool (where you would need to become a member first).