You might want to explore putting your reserve funds into Money Market (MM) or Certificate of Deposits (CD) before getting involved in the complexities of Treasury bonds. MMs and CDs are each insured up to $250k so there no loss of principle. Depending on how frequently you estimate you will need to draw on the funds, you can look at on-line "internet" banks or local brick and mortar banks.

If you're in NYC, I can make a recommendation. Bethpage Federal Credit Union. They were originally Long Island only, but have a full service branch in Chelsea on 26th St. I used them for personal banking long before becoming my Co-op's treasurer, and opened a business account with them for our reserve funds. Here's the link to their business banking department: https://www.bethpagefcu.com/business.aspx and the link to their business account rates https://www.bethpagefcu.com/rates-calculators.aspx . BFCU Money market is paying 1.75% and you have immediate access to your funds. CD's are tiered based on length of time. They were a little slow raising their interest rates compared to other banks, but in the past year the latency has decreased.

I've been with the BFCU (personally) since 1974 (I'm an oldie but goodie) and never had any problems or fund security concerns. They're one of the largest credit unions in the country.