The Dow Jones Industrials (DJINDICES:^DJI) fell 24 points, or just over 0.1%, on Monday to close at 17,623. Three stocks accounted for the lion's share of the downward pressure on the Dow, with Apple (NASDAQ:AAPL) leading all 30 Dow stocks downward in terms of percentage declines. Energy stocks Chevron (NYSE:CVX) and ExxonMobil (NYSE:XOM) were also substantial losers on the day, falling more than 2% each.

In the following slideshow, you'll find a short explanation of what happened to the Dow and these three stocks. Although a single day's movements aren't always important to your long-term investing strategy, it still makes sense to track what's happening with the stocks in your portfolio to make sure that you don't get blindsided by unexpected bad news -- especially during turbulent periods like peak earnings season.