An old Wall Street saw has it that nobody ever went broke taking a profit. Here’s a more specific rule for long-term stock investing success: Once your stock has broken out, take most of your profits when they reach 20% to 25%. IBD founder and Chairman William O’Neil formulated the rule in the early 1960s, when he noticed that most stocks broke out of well-formed bases, ran up 20% to 25%, then corrected sharply in price.