Try to extract money from a hedge fund manager or the founder of a private equity fund and he loses all sense of proportion.

The first example came in July when Stephen Schwarzman, the co-founder of Blackstone, compared the US government’s attempt to increase the amount of tax paid by the partners of financial firms to Adolf Hitler’s invasion of Poland in 1939. Mr Schwarzman had to apologise for the analogy, made privately to the board of a non-profit group.

The second came last week when Daniel Loeb, founder of the hedge fund Third Point, described a proposed change in the taxation of sales or initial public offerings of such funds as an “arguably unconstitutional Bill of Attainder” that showed the Obama administration was “operating from a playbook quite different from the one we are used to as American business people.”