Chris Eubank Jr will be fined £375,500 ($500,000) after missing the weight by just 0.05lb for Saturday’s grudge match with Conor Benn.
The 35-year-old weighed 2lb over the 11st 6lb limit on the first attempt and was still too heavy the second time.
A trimmed and toned Benn – who has operated at welterweight for most of his career – came in lighter than expected at 11st 2lb.
Eubank and Benn are both bound by a rehydration clause that prohibits them from weighing more than 12st 1lb on Saturday morning.
“Show me the money”, Benn posted in a video on social media.
The weigh-in took place behind closed doors at a London hotel on Friday.
There will be a ceremonial weigh-in, which will be open to the public, in Islington on Friday evening.
The fight is due to take place at Tottenham Hotspur Stadium.