I don't like USDT and I don't believe that it's properly backed. There were a lot of controversies on the topic, but I stopped following all the relevant news. So.. be careful.

However, the main reason for me replying here is different. And from a quick check it seems like nobody mentioned this.
You seem to want to invest into USDT. Do you know that being a stablecoin means that its price should (normally) remain in parity with USD, hence not a good investment?

USDT is normally a pretty good tool for traders, but imho not that much suitable for investing/holding, since you won't gain anything.
(Of course, if you want to hold USDT only in the days Bitcoin price is dropping, then it's a different story.)