What is a ratio call spread, and why does it have unlimited upside risk?

A ratio call spread involves buying calls at a lower strike and selling a greater number of calls at a higher strike, typically in a 1:2 ratio. This creates a net credit (or reduces cost) but introduces unlimited upside risk because the extra short calls are uncovered.\n\nStandard Construction (1:2 Ratio):\n\n- Buy 1 call at strike K1 (lower)\n- Sell 2 calls at strike K2 (higher)\n\nThe position is partially bullish (profits from moderate price increases) but becomes short above K2 because the extra uncovered call creates unlimited exposure.\n\nWorked Example:\n\nQuorum Analytics trades at $50. Trader Ines builds a 1:2 ratio call spread:\n\n| Leg | Strike | Premium | Quantity |\n|---|---|---|---|\n| Buy call | $50 | -$3.80 | 1 |\n| Sell call | $60 | +$1.50 | 2 |\n\nNet premium: (2 x $1.50) - $3.80 = $3.00 - $3.80 = -$0.80 net debit\n\nPayoff Analysis at Expiration:\n\n| Stock Price | Long $50 Call | Short $60 Calls (x2) | Net Payoff (per share) |\n|---|---|---|---|\n| $45 | $0 | $0 | -$0.80 |\n| $50 | $0 | $0 | -$0.80 |\n| $55 | +$5.00 | $0 | +$4.20 |\n| $60 | +$10.00 | $0 | +$9.20 |\n| $65 | +$15.00 | -$10.00 | +$4.20 |\n| $70 | +$20.00 | -$20.00 | -$0.80 |\n| $80 | +$30.00 | -$40.00 | -$10.80 |\n| $100 | +$50.00 | -$80.00 | -$30.80 |\n\nMaximum Profit:\nOccurs at K2 ($60): Long call value ($10) - Net debit ($0.80) = $9.20\n\nBreakeven Points:\nLower: K1 + Net debit = $50 + $0.80 = $50.80\nUpper: K2 + Max profit = $60 + $9.20 = $69.20\n\nWhy Unlimited Risk Exists:\n\nAbove the upper breakeven, the position loses $1 for every $1 increase in stock price (net short 1 call). Above $60, the two short calls gain intrinsic value at $2 per $1 move, while the single long call only gains $1. The uncovered short call has theoretically unlimited loss potential.\n\nRisk Management:\n- Some traders convert to a 1:2 at zero cost (adjust strikes until net premium = $0)\n- Setting a stop-loss at the upper breakeven is common\n- The strategy works best in moderately bullish environments where the trader expects the stock to settle near K2\n\nKey Distinction: The ratio spread differs from a vertical spread because the number of contracts sold exceeds the number bought, creating naked exposure.\n\nExplore ratio strategies and their risk profiles in our CFA Derivatives course.