Wait 30 Days After Warnings

Editor's note: As a special bonus to TheStreet.com readers, we will be running an updated version of Jim Cramer's "Twenty-Five Rules of Investing," from his latest book, Real Money: Sane Investing in an Insane World. Here's Rule 22.

Few rules have saved me more than the 30-day preannouncement rule.

When Tibco Software(TIBX Quote) preannounces a bad quarter, do you rush to buy it? Are you someone who put money to work in Waters(WAT Quote) right after its vicious preannouncement in spring 2005?

If you are, this rule is for you: ...