A tradesman on the verge of bankruptcy would come to him, Verminet would look into his case and make him sign bills for the sum he required, handing him in exchange bills drawn by other tradesman in quite as serious a predicament as himself, and pocketed a commission of two per cent.

upon both the transactions.

Verminet obtained clients from the simple fact that an embarrassed tradesman is utterly reckless, cares not what he signs, and will clutch at a straw to keep his head above water.
But there were many other transactions carried on at the office of the Mutual Loan Society, for its largest means of income was drawn from even less respectable sources, and it was alleged that many of these bogus bills which are occasionally cashed by some respectable bankers were manufactured there.

At any rate, Verminet managed to make money somehow..