Understanding Buy Zones: How to Time Your Stock Entries
Knowing a stock's fair value is only half the battle. The other half is knowing when to buy — and at what price. That's what buy zone analysis solves.
What Are Buy Zones?
Buy zones are price ranges that correspond to different levels of margin of safety relative to the estimated fair value. They help you answer: "Given this fair value, what price should I be willing to pay?"
Convex calculates five zones:
- Strong Buy — Deep discount to fair value (typically 30%+ below FV). Maximum margin of safety.
- Buy — Meaningful discount (typically 15-30% below FV). Good risk/reward.
- Accumulate — Modest discount (typically 5-15% below FV). Worth adding to an existing position.
- Hold — Near fair value. Not compelling to buy, but not a sell either.
- Overvalued — Trading above fair value. Risk/reward is unfavorable for new positions.
How Buy Zones Are Calculated
The zones are derived from the fair value estimate, adjusted for:
- Stock classification — Growth stocks have wider zones (more uncertainty), blue chips have tighter zones
- Quality score — Higher quality businesses deserve a smaller discount (they're worth paying up for)
- Fair value confidence — When the three valuation methods agree, zones are tighter; when they diverge, zones are wider to account for uncertainty
Using Buy Zones in Practice
Buy zones are most useful when combined with the rest of the conviction framework:
- Run a full conviction analysis on a stock
- Check the conviction score — is it high enough to warrant a position?
- Look at the current price relative to the buy zones
- If the stock is in the Score A or Score A+ zone and has high conviction, it is within the modeled value range
- If it's in the Score A zone, it is within the modeled accumulation range
- If it's in the Fair Value or Overvalued zone, the price is above the modeled entry range
Patience Is an Edge
The best investors know that waiting for the right price is a superpower. Buy zones give you the discipline to wait — and the confidence to act when the time is right. Instead of chasing momentum or buying on hype, you're buying when the math is in your favor.