Fidelity CMA balances are swept into FDIC-insured bank accounts. One trick with this account is that you can purchase Fidelity Money Market funds, which are treated as cash, and which Fidelity will auto-liquidate as-needed to cover debits, without intervention on your part. You can select any Fidelity Money Market fund for this. SPRXX, for instance, currently pays 2.09%. Plus you get a debit card that refunds any ATM fee in the world, free wire transfers, bill pay, paper checks (if needed), and competent customer service that's available 24 hours per day.