Bank Robbery

Two accountants were in a bank when a gang of armed robbers burst in. While some of the robbers snatched bundles of cash from the tellers, others lined the customers up against the wall and relieved them of their wallets, watches, and other valuables.
As the robbers made their way down the line, one accountant pressed something into the hand of the other accountant. “What’s this?” said the second accountant without looking down.
His colleague replied: “It’s that $100 I owe you.”