Poor Dad Rich Dad

If you can borrow at 4 percent and lend at 6 percent, you can sign both contracts and pocket the 2 percent spread—risk-free. It's pure arbitrage with zero capital out of your own pocket.

When does this game break down? When one side defaults—for instance, you lend out at 6 percent and the borrower can't pay back. Then the person who lent you the money comes knocking.

If the demand is small, you cover it yourself; that's your margin, your capital pool. But if it's large enough, take a look at what happened to Hu Xueyan.

So a businessperson's focus is on funding cost and maturity mismatch. Whether you lose money on a bad trade isn't the priority—as long as the game of moving money left to right keeps running, you stay wealthy.