There was a post somewhere comparing the different earnings potentials of checking, money market, and CDs. But that assumed you were starting at the first dollar. I'm trying to figure out what makes sense for money over $200K now. I'm basically ignoring the FDIC issue, but just looking at the miles given for checking and CDs at BankDirect. I'll also ignore the interest since it's negligible. Put $100,000 in a checking account at BD that already has $200,000 in it, and you'll get 4000 additional miles per month. That's 48,000 miles per year. Put $100,000 in a one year CD at BD and you'll get 50,000 miles immediately. (Side note: if interest rates don't change on the checking, you'll also get $50 more over the year via the CD.) Once I broke it down, I'm not sure I sold myself on the CD. You get the miles upfront, which is nice, but your money is locked in for a year. On the flip side, where BD could change the miles calculation again on the checking, you lock that ratio in on the CD. Since I still have a BBVA account that gets, now, a mile for every $18, I think that's the plan. Better reward (66,666 miles over the course of the year) and flexibility. Anything wrong with my math?