PEG Ratio: The Growth-Adjusted P/E That's Less Naive Than It Looks

The Objection to PEG and the Fix

The standard critique of PEG (P/E divided by EPS growth rate) is that it ignores balance sheet, capital intensity, and margin durability; that the EPS-growth input is easily manipulated by buybacks; and that it behaves badly when growth is close to zero. All of that is true for naive PEG. The tool stays useful once you (a) use *long-term* EPS growth not next-year, (b) decompose the growth into organic vs share-count-driven, and (c) apply PEG only inside a profit-consistent peer group. The PEG card on alphactor.ai enforces all three.

What the PEG Card Shows

The PEG card plots four PEG variants side by side: forward-P/E over sell-side 3-year-EPS CAGR (the classic Lynch version), forward-P/E over internal 5-year EPS CAGR, a growth-quality-adjusted version (EPS growth decomposed into revenue, margin, and buyback effects), and the peer-group median PEG for normalization. The headline number is green when below 1.0, yellow 1.0–2.0, red above 2.0 — same thresholds Lynch used, but the interpretation is now tier-aware.

Reading the Signal

Three setups make PEG useful rather than misleading. First, PEG < 1 with organic-growth > 70% of total = a real bargain on a real grower; most "bargain" PEGs are driven by buyback-inflated EPS and don't count. Second, PEG > 2 with decelerating growth — growth is shrinking toward the denominator, so the ratio is understating the multiple's risk. Third, PEG converging to peer median from below (was 0.6, now 0.9 while peers sit at 1.1) signals the discount is closing — fine for a holder, poor entry for a new buyer.

Where It Fits

Use PEG alongside EV/Revenue for pre-profit names where PEG doesn't compute, Rule of 40 for SaaS-style operational quality, and Reverse DCF to cross-check that the growth the market is implying lines up with the growth you're paying for via PEG.

Open the PEG card → /app/stocks/AAPL/fundamentals