AUM is the absolute wrong metric to measure for an exchange. This is why I tell everyone to never pretend they understand a subject the moment you read the first Wikipedia page you come across.

All crypto is < 1T. I don't know what their market share is, probably high 100Bs.

All crypto is > 2T, as of the last few days

USD 90 billion "assets on platform" (which, as has been pointed out, is not a good metric for an exchange at all). That's about 5-12% of total crypto assets (depending on the time of day) [1].

By the way, Coinbase revenue in the last quarter was nearly 0.1% of the entire crypto market cap.

So, Coinbase took around 60$ of any 10,000$ traded on Coinbase, and 10$ of any 10,000$ crypto market cap, which implies that 1/6 of the entire crypto market cap traded through Coinbase once this quarter, unless I'm mistaken.

See the second story in Matt Levine's Money Stuff: https://www.bloomberg.com/opinion/articles/2021-04-14/good-a...

[1] more likely, the percentage is fairly constant, while the USD value fluctuates a lot with crypto prices, so "AUM" might be around USD 200 billion now (as crypto market cap is USD 2 tr).