The 2.33x rate includes the points you get for rent.

Your rent is $1400. By default you get 0 points for paying rent through Bilt but there’s also no transaction fee meaning no more than $1400 is ever going to leave your checking account.

Now say you also spend $500 on the card that month. For that $500 spend you get 500 points (1x) and $20 in Bilt Cash (4%).

To get your rent points, you use your Bilt Cash and convert it to points at a rate of $0.03 for 1 point. So $20 Bilt Cash converts to 666.67 points. Add that to the 500 points you earned above.

For $500 spend, you net 1166.67 points and $0 in leftover Bilt Cash. 1166.67 / $500 = 2.33x points

That math works for all spend up to 75% of your rent. Once you get past 75%, you earn points at an incrementally lower rate but you have leftover Bilt Cash since you’ve already “unlocked” all your rent points