The Dow Jones Industrials (^DJI -0.11%) 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 (AAPL 1.27%) leading all 30 Dow stocks downward in terms of percentage declines. Energy stocks Chevron (CVX 0.44%) and ExxonMobil (XOM 0.02%) 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.

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If you're like most Americans, you're a few years (or more) behind on your retirement savings. But a handful of little-known "Social Security secrets" could help ensure a boost in your retirement income. In fact, one MarketWatch reporter argues that if more Americans knew about this, the government would have to shell out an extra $10 billion annually. For example: one easy, 17-minute trick could pay you as much as $15,978 more... each year! Once you learn how to take advantage of all these loopholes, we think you could retire confidently with the peace of mind we're all after. Simply click here to discover how you can take advantage of these strategies.