[Majromax]

True, but from the pdf it seems like the fee charged of market makers is 1.75¢ × P × (1-P) per contract. Near P=0 that's approximately 1.75% of the notional amount invested, but near P=1 that's approximately 1.75% of the potential gain.

As I read it, the implication is that a market maker in the high-P regime needs to still have an expected edge of 1.75% to profit net of fees, which means that the 'maker return' table in this article is net negative after fees for all categories save for entertainment, media, and world events.

[hardluck]

Fees are also waved if a market maker hits a certain monthly quota. With the recent adoption of “professional” market makers on the platform, I’m sure they can get around such fees.

I will also add to the 2nd point that some of these platforms due give fixed interest to positions in unresolved markets.