Fund manager Randy Work has asked judges to weigh the value of his "genius" as he tried to get a bigger slice of his family's $US225 million ($297 million) fortune than his ex-wife. He lost.

The former Lone Star Funds executive failed to convince a three-judge panel at his divorce appeal in London this week that his "special contribution" during their marriage meant he was entitled to a bigger share than the typical British practice of awarding a 50-50 division of marital assets.

Multi-millionaire Randy Work complained his ''special contribution'' to the creation of the couple's fortune had not been recognised. Credit:Jonathan Brady/PA Wire

Work and Mandy Gray, both American, were married for 20 years when they split. A lower-court judge said in 2015 that the multimillion-dollar estate should be equally split because while Work may have worked hard, the fortune was the result of "being in the right place at the right time, or benefiting from a period of boom," not his professional brilliance.

The appeal judges agreed, saying the use "of the word genius is unhelpful," and that Work "failed to demonstrate that" the previous judge's "decision was wrong."