Acca insurance

A bookmaker promotion that refunds a stake (often as a free bet) when an accumulator loses by a single leg. Typical terms: 4+ leg accas, minimum odds per leg, maximum refund £10-£25. Acca insurance is marketed as a risk-reduction tool but is structurally a free-bet conversion mechanism — the expected value of the refund is well below the compounded margin you pay into the acca.