With loompoints going for 1.6mil atm if you put up an offer for a +3 for 2.5 looms worth of gold (4mil gold) the tax is 200,000 gold. So to trade atm you need loompoints, which pushes their value up even more because people don't want to lose so much gold in tax
While on the subject is there any chance you can make retiring more appealing to people so they produce more looms? Lower STF, more looms when you retire etc