Or maybe you think of some non-Nasdaq superstars with high prices and high betas. For instance, some recent darlings include Goldman Sachs (GS - commentary - Cramer's Take) and Bear Stearns (BSC - commentary - Cramer's Take).

All of these examples make sense, and if you have been long these stocks over the past six months, you're feeling pretty good about things. However, it would probably shock you to know that the chemical sector has been every bit as strong as these highfliers.

If you were one of the lucky investors who rode the chemical group higher, it's time to pay attention to the near-term signal that is saying, "Slow down." Let's understand why.

As you can see from the chart below, the Dow Jones U.S. Chemicals Index raced up a little more than 20% in only six months. (Some components of this index include Air Products (APD - commentary - Cramer's Take), DuPont (DD - commentary - Cramer's Take) and Dow Chemical (DOW - commentary - Cramer's Take).) That's quite a move, and you can see that it basically never had any sustainable pullback. That's understandable, however, when you note that the MACD remained strong, making higher highs on the way up after even the smallest pullback.

Suddenly and without warning, it put in a double top in price at 237, but for the first time, the MACD refused to confirm the move. That's clearly visible on the chart. Here's the red flag: After pulling back a bit, the index came back up and retested the top, but the MACD did not move up with price. That tells us to be extremely cautious here.

Taking a Breather Here's a chart of the Dow Jones U.S. Chemicals Index

Click here for larger image.

Source: StockCharts.com