If US Treasuries at yielding 4-5% right now, why can't I find a 1 month US Bond ETF or 6 month US Bond ETF that yields 4-5%? The best I can find is
SGOV but it only yields 2%.
Over the last 12 months, SGOV yielded 1.84%, but the current SEC yield (30 days ending on the last day of last month) is 4.41%. If you want to know what a fund or ETF yielded most recently, look at the SEC yield.
The average yield to maturity of SGOV is
2% is the 12-month trailing yield. From https://www.ishares.com/us/products/314116/ishares-0-3-month-treasury-bond-etf:
Note that the average yield to maturity of SGOV is a bit lower than newly issued Treasury bills, as the yield to maturity has been increasing steadily over the past 1 year. From https://ycharts.com/indicators/3_month_t_bill:
If you're trying to immediately capitalize on higher rates, your best bet might actually be a money-market mutual fund in the current environment. These funds have access to the Fed's Overnight Reverse Repo ("ONRRP") facility for parking their excess cash, and as of the most recent rate hike, the ONRRP facility is paying 5.30%.