In his April 29, 2025 video, about "Paper Bitcoin",
@Matthew Kratter argues against the existence of paper Bitcoin, showing an image with BTC distribution across exchanges and banks, including Revolut. (See image below)
I have personal experience with a Revolut account (the App) only allowing $2K worth of BTC per day to a hardware wallet.
Buying $25K BTC in the Revolut App will take you 10 days to withdraw to self custody. Why would Revolut do this? Because of fractional reserving, or paper Bitcoin. You THINK you have $25K in BTC, but Revolut only bought $2K, $5K or $10K worth, so when you start to withdraw, Revolut delays the process and buys more BTC to "fill their reserves" measured over all customers. This is very dangerous and exactly the reason why banks fail.
So while Revolut may indeed have 28543 BTC at Coinbase, nobody knows how much 'paper BTC' they have sold in their App to customers. My experience with Revolut indicates that they are selling more, they are levered up.
Revolut's crypto terms and conditions explicitly state: "We may limit the amount of cryptoassets you withdraw. We will tell you the amount of any limit before we accept your instruction."