Legendary money manager Ken Fisher outlines the most common—and costly—mistakes investors make.

• Small cap stocks are best for all time. Bunk!
• A trade deficit is bad for markets. Bunk!
• Stocks can't rise on high unemployment. Bunk!

Many investors think they are safest following widely accepted Wall Street wisdom—but much of Wall Street wisdom isn't so wise. In fact, it can be costly bunk.

In Debunkery: Learn It, Do It, and Profit From It—Seeing Through Wall Street's Money-Killing Myths, Ken Fisher—named one of the 30 most influential individuals of the last three decades by Investment Advisor magazine—details why so many investors fail to get the long-term results they desire. The short answer is many investors fail to question if what they believe is true—and are therefore blinded by tradition, biases, ideology, or any number of cognitive errors.

Your goal as an investor shouldn't be to be error-free—that's impossible. Rather, to be more successful, you should aim to lower your error rate. Debunkery gets you started by debunking 50 common myths—but that's just the beginning. It also gives you the tools you need to continue to do your own debunkery for the rest of your investing career.

KEN FISHER is the Founder, Executive Chairman, and Co-Chief Investment Officer of Fisher Investments, a $387-plus billion (as of 3/31/2026) investment adviser and money management firm serving large institutions and high-net-worth individuals. For over 32 years, Fisher wrote Forbes' "Portfolio Strategy" column, making him the longest continuously running columnist in the magazine's venerable history. He now writes monthly, native-language columns in over 25 major media organs worldwide, including the New York Post, Britain's Daily Telegraph, Spain's elEconomista and Italy's Il Sole 24 Ore. In total, his columns span more countries and more languages in more total reach than any other, non-syndicated columnist of any type ever.

LARA HOFFMANS is a content manager at Fisher Investments, a contributing editor of MarketMinder.com, and coauthor of the bestsellers, The Only Three Questions That Count, The Ten Roads to Riches, and How to Smell a Rat.