Slippage due to very thin orderbooks. If you also take into consideration that most orders in the books that we see are spoof orders, which bots pull back when the price comes to their trigger price, you need even less fiat or tether to pump the price with.

In the same way, if people start selling like what happened late last year, you need the billions of circulating Tethers to provide buy support on exchanges like Bitfinex, Binance, OKEx, Huobi, etc. If there was no Tether but only actual fiat in the market, we without a doubt would have seen the price tank DEEP under the $3000 level, and perhaps even under the $2000 level.

People don't want to hear or admit it, but Tether is literally propping up the market.