@hxxntrr If it drops 25%, you get a margin call and a forced sale taxed at the 28% collectibles rate. The only guaranteed profit here is the "funding" fee.
@hxxntrr Borrowing isn't taxed, but neither is unrealized gain on gold. There's no tax being "avoided," just a leveraged gold bet. Card surcharges (4%), dealer spread, 5-8% loan interest, and the $50K still left on the cards mean gold has to rise 10-20% just to break even.