Already mentioned a few times in this thread, most recently only one week ago.
The 4-week T-Bill is ~2.14% now, while the best savings account is 2.53% (NASB). If you can’t get that savings account, then the 4-week T-Bill probably makes sense. IMO, the 13-week T-Bill (2.54%) is an even better bet, since the next FED meeting is 7 weeks away and the one after that is 13 weeks away and I don’t expect a whole lot of movement from the savings accounts between now and the first meeting. The 26-week T-Bill (2.93%) is even better, since I don’t think even shifting between the best savings accounts would beat it over the next 26 weeks. But this is a Savings Accounts thread. The longer-term T-Bill discussion is probably more appropriate in the CD discussion thread.