Subject: Re: $STEW at 23% discount
...AND public companies issuing zero coupon bonds...

Of course, Mr Buffett was the first one ever to sell negative coupon bonds. He's ahead of the pack.
Though the SQUARZ securities had interesting terms, in effect he was writing call options 15% out of the money in return for float. At the time he did so, price-to-known-book was 1.975, and the exercise price (good for five years) was 2.27 times the starting P/B.

Jim