Hi, yes Citibank work in the same way. I used to regularly exceed my citibank credit limit for short periods sometimes and never got charged an overlimit fee. it would allow transactions over the credit limit by around $5k. after about $5k, future transactions would be declined. later on they increased my credit limit, and now I don't exceed the limit. Online banking is set to automatically not allow you access to the rewards pages as soon you exceed your limit, but access automatically comes back again once you are under your limit.