[turingcompeteme]

It was never about returns exceeding borrowing costs. Rentech is probably the greatest money manager of all time. They can make returns that exceed the borrow costs.

It was always about the amount of borrow available, and the tax paid on the gains. The (illegal) strategies they used allowed for much larger borrow amounts, as well as only paying long term capital gains, when in reality there were millions of trades.

The simple setup: Rentech pays the bank $1B for a call option. The call option is on a $10B pot of money. The bank then hires Rentech to invest the pot of money for them. After a year or two, Rentech then exercises it's call option, which gives it everything in the pot except the bank's $9B plus a fee. The banks loved this fee. And since this was a year long call option, all gains are taxed as long term. They avoided $6B in taxes doing this.