When to Sell a Stock
6 min read · Winvestor Analyst Team
Four rules our analysts use to decide when a thesis is broken.
Rule 1: The thesis is broken
Write down why you bought a stock the day you buy it. Sell when the reason no longer holds — a moat erodes, a key product fails, management you trusted leaves, or accounting raises red flags. Price falling is not, by itself, a broken thesis. Fundamentals breaking is.
Rule 2: A materially better opportunity appears
Capital is finite. If you find a company you understand better, with stronger growth and a more attractive valuation, it's rational to rotate — even if the current holding is still 'fine.' Just be honest that you're upgrading, not chasing performance.
Rule 3: Position size has gotten out of hand
If a winner has grown to 20–30% of your portfolio, trim it back to a level where a 50% drawdown wouldn't derail your plan — typically 8–10% per single name. You're not betting against the company; you're respecting concentration risk.
Rule 4: You need the money for life
If you're approaching a major expense — house down payment, tuition, retirement spending — sell what you need on a planned schedule. Markets don't care about your timeline, so don't let them dictate it.
Reasons that are NOT good enough
'It's up 30%, I should lock in gains.' 'It's down 20%, I want to stop the pain.' 'A pundit on TV said so.' 'It's been flat for six months.' None of these are sell signals. Holding through volatility is where the compounding happens.