How to Make Money in Stocks — Chapter 6: The Complete Sell Discipline

"Buying is art; selling is discipline. Most people study how to buy their whole lives and never seriously think about how to sell." — William O'Neil

Financial Context

O'Neil observed a universal pattern: investors spend dozens of hours researching whether to buy a stock, then sell on whatever they feel at the moment. Buy decisions have a basis; sell decisions do not — and selling is the half that actually determines returns.

This chapter separates selling into two distinct problems.

Wall Street Application

1. Defensive vs. Offensive Selling

| | Defensive sell | Offensive sell | |---|---|---| | Trigger | Loss reaches 7%–8% | Gain reaches 20%–25%, or a topping signal | | Purpose | Limit loss | Lock in profit | | Psychological difficulty | Admitting error | Forgoing further upside | | Negotiable? | Never | Adjustable with trend strength |

The key distinction: defensive selling is a hard rule; offensive selling is adjustable judgment. Conflating them is the common error — treating the stop as "maybe wait a bit longer" and the profit target as mechanically binding gets it exactly backwards.

2. The Eight-Week Hold Rule

One of O'Neil's empirical rules: if a stock gains more than 20% within three weeks of its breakout, hold it at least eight weeks.

The logic: such rapid initial strength usually marks a genuine institutional leader whose advance far exceeds the routine 20%–25%. The rule exists to prevent your normal profit-taking discipline from cutting short the handful of positions that generate outsized returns.

3. Setting Trailing Exits

• The 50-day average: Leaders typically ride their 50-day line higher. A high-volume break that fails to recover within days is a sell signal.
• Trendline breaks: Connect the rising lows; a decisive break warrants reducing.

4. Why Selling Is Harder Than Buying

Buying confronts possibility; selling confronts realized outcomes — profit makes you greedy, loss makes you stubborn. This matches the disposition effect in Reminiscences Chapter 3 exactly.

The only effective remedy is writing sell rules before buying, while you hold no position and judgment is uncontaminated by gain or loss.

Trading Execution Rules

1. Write three prices before entry: the stop, the routine profit target, and the condition that switches you to a trailing exit after a fast advance.
2. Separate the two sell types: execute defensive sells mechanically; adjust offensive sells to trend strength.
3. Never delay a sale for taxes: holding a broken position to avoid tax usually costs more than the tax.

Relevance to a Retirement Portfolio

The practice worth adopting is writing the sell condition before buying.

The most common problem in retirement portfolios is not buying badly but never having defined a sell condition — holdings persist for years through inertia, neither actively favored nor actively removed. Putting rebalancing rules, allocation caps, and withdrawal ordering into a written plan in advance is the long-term investing equivalent of O'Neil's discipline.