When should the referee stop a fight?

Regulation 27(6)(b) of the Boxing Regulations says the referee stops the fight, or ends it, when:

• the bout is one-sided, even if the losing boxer hasn't yet taken excessive punishment (award it to the better boxer);
• a boxer is accidentally disabled or unable to defend themselves (award it to the opponent, subject to the foul and injury rules);
• a boxer goes down three times in the same round from legal blows;
• a boxer is counted out (doesn't rise by the count of ten);
• a boxer acknowledges defeat: can't continue at the timekeeper's signal, turns their back, or signals they don't want to go on;
• the chief second throws in the towel;
• a boxer knocked out of the ring doesn't get back in unassisted within 20 seconds (loser by knockout);
• a boxer commits a serious foul (warn or disqualify);
• one or both boxers are not boxing to the best of their ability (disqualify);
• a boxer goes down without being hit, or stays down without just cause (count to ten without saying "out", then disqualify).

If a boxer retires during an interval, the opponent wins by TKO in the next round (regulation 35(18)). When a fight doesn't go the distance, only the referee gives the decision, and it is final.