Risk of ruin in betting

Risk of ruin is the probability that a bankroll hits zero, or an unusable level, before your edge can express itself. It rises sharply with stake size.

Three inputs drive it: edge, volatility and stake as a fraction of bank. Doubling your stake percentage does not double ruin risk — it multiplies it, because deeper troughs compound. This is the mathematical reason professionals stake small percentages that look timid to recreational bettors.

Ruin risk falls roughly exponentially as bankroll units per bet increase; more units of bank per stake means dramatically more survivability.

A 2% edge staked at 1% of bank carries a very low ruin probability over thousands of bets. The same 2% edge staked at 10% of bank has a substantial chance of ruin inside a single season, purely because an ordinary run of eight losses removes more than half the bank.

Survival is a precondition for profit. Every other calculation assumes you are still betting next month.

Small starting bankrolls plus large minimum stakes make ruin risk unusually high for new Nigerian bettors. Fewer, better-priced bets at a smaller share of bank is the correct adjustment.

• Assuming a positive edge makes ruin impossible.
• Ignoring correlated bets placed on the same weekend, which behave like one large stake.
• Reloading the bank from income and calling the strategy break-even.