Here are couple of links that should school you up along with some highlights of what I know.
1. 10,000 limit per year per person. However, you could potentially do $30k/year if your married and have a trust. Also, there is a provision where you can put your tax refund toward I bond purchase - maybe $5,000 per year?
2. Interest rate changes every six months. Rate is composite with a fixed portion (currently 0%) and variable portion. Variable is projected to be near 10% beginning in May. Who knows what it will be in November - based on inflation. Some recommend buying now (in April) as current rate is a little over 7%. You will get that rate for first six months and the nearly 10% rate for second six months. If you buy in May, you’ll get nearly 10% for May-October, but who the Nov 22-April 23 rate will be?
3. Must hold at least one year. If you cash out prior to five years, you forfeit the last three months of interest prior to cashing.
4. No state or local taxes. Is taxable at federal level.
Not a bad idea to park some unneeded cash imo. Please read links and forgive me if I misspoke. Also, there are several similar articles on the web.
https://www.treasurydirect.gov/indiv/products/prod_ibonds_glance.htmhttps://www.bloomberg.com/news/news...ation-linked-bond-yields-set-to-increase