1. Pay $5,000 tax due using Starwood Amex and pay $124.50 in fees.
2. Pocket 10,000 Starpoints.
3. Do a balance transfer to another credit card with 0% interest for 12 months, no transfer fee.
4. Put $5,000 in an HSBC savings account (4.80% APY) or get a 12 month CD. Total return after 12 months = $240
5. Net: $240 (interest earned) - $124.50 (fee) = $115.50
6. Total: $115.50 + $125 (assuming 10,000 Starpoints worth $125) = $240.50