How can I have diminishing multiplicative stacking that caps at 150% instead of 100%?

This is for designing a video game. There's lots of things you can get that give you buffs. Let's say each thing you get gives you a 6% buff. And I want it to stack diminishingly but I don't want the limit to be 100% i want it to be 150%. So the first one is 6% then the second stack would be somewhere between 12% and 11.64% (where it would be if the maximum was 100%). More specifically I'm looking at (1-0.94^36) and getting about 0.89. I want each individual piece to remain 6% but I want the total to be able to go above 100% and be much higher than 0.89.

How would this be written? Also no idea if i flared this right.