The Most Expensive Mistake in a Bull Market Is Selling a Winner Too Soon

An investor buys a stock at $20 and sells at $40. A 100% gain. Then the stock reaches $60, $100 and eventually $200.

The investor made money. But a $10,000 position that could have grown to $100,000 ended with $20,000.

That is the regret behind selling too early. You were right about the opportunity, owned the shares, and walked away before the largest gains arrived.

The difference between a 2x and a 10x is enormous. A $10,000 investment becomes $20,000 at 2x, $50,000 at 5x and $100,000 at 10x. The initial investment is identical. What changes is how long the investor stays in the position.

The hardest part is that selling at a profit feels responsible. After doubling your money, protecting the gain seems sensible. After tripling it, the thought of giving some back becomes even harder to tolerate. Meanwhile, every new high makes the decision to sell look worse.

The market rewards investors who recognize a winner, but the largest returns often go to those who can hold through the discomfort of watching their gains fluctuate.

There is a reason this matters beyond individual stocks. Wells Fargo Investment Institute examined the S&P 500 over the 30 years ending June 2025. The index returned an annualized 8.45%. An investor who missed the 10 best trading days earned 5.56% annualized. Missing the 30 best days reduced the annualized return to 2.07%.

Source: https://www.wellsfargoadvisors.com/research-analysis/reports/policy/volatile-markets.htm

Those figures measure the cost of missing the market’s best days, not specifically the cost of selling one winning stock too early. But they reveal how a small number of powerful advances can account for a disproportionate share of long term returns.

Another trap is selling winning positions to lock in gains while holding losing investments in the hope they will recover. The portfolio ends up cutting short its best performers while giving its worst performers more time and money. Over time, that habit can leave investors with less exposure to the companies driving their returns.

Selling part of a position can ease the pressure to cash out completely. Taking some profit reduces the amount at risk while leaving shares invested if the stock continues climbing. The remaining position can still turn a 2x winner into a 5x or 10x winner, without requiring.