joel greenberg actually moved into the treasury bill pit and became a very, very large trader there for a while as el with. >> and so what did you trade? >> i started off -- i came back to chicago, i worked as a clerk for a few months, then leased a seat. and i started trade anything gold futures. gold futures were actually the second large itself -- largest volume product at the mercantile exchange. part of it was during those days people were utilizing what they called gold spreads, buy withing one contract, selling another as a vehicle to defer charges. >> and by deferring, you mean not pay. >> yes. [laughter] you're able to use gold contracts to essentially take a tax liable from one year and move it into the next year. and some people did that year after year after year. the problem was, eventually, the government took their regulations, and people could no longer roll their taxes. so times people want to put multimillion dollar tax bills that were immediately due. >> okay. >> so, and quite honestly, i think, that was the end of the ability to roll backses through gold spreads