• New customers who hadn't opened a Moomoo brokerage account before Jan 1, 2026.
• You must be enrolled in the Cash Sweep program to earn interest on uninvested cash.
• The 4.5% APY booster coupon has to be activated by hand in the app (My Rewards). If you don't, it expires.
• The boost lasts 60 days from activation and only covers the first $20,000.
• The 3.6% base rate applies with the booster. After it ends, the base continues only with a moomoo engine subscription. Otherwise it drops to 0.03% APY.
• Rates are variable. Moomoo's page lists the base as 3.6% as of Sep 18, 2026.
• Swept cash is FDIC-insured through program banks (not SIPC) once it leaves your brokerage account.

Interest at 8.1% on $20,000 for 60 days = $266.30. The calculator subtracts what the same cash would earn elsewhere. The base rate (3.6%) can change.

Why we say DEAL: If you have cash that would sit anyway, two months at 8.1% beats a savings account by roughly $100 on $20K. Mark your calendar for day 60, when the boost ends.