Originally Posted by DrJekyll MrHyde

While 4% is a decent amount of holdback for a PBS system, by my estimation is considerably less than we have leftover in the OT pot now when trading begins. After OT Live begins for the month and a people cram in a few more trips, I think little is leftover in the OT Pot.

So, less trips in the OT Pot means less aggressive bidding for reserves.

I think the 4% holdback is a small perk for having something to swap with in the OT Pot. But more importantly it allows PBS to have up to 4% of trips leftover when it creates its solution, minimizing the need to unstack and assign leftover trips.