Monero (thanks to its untraceability) was a primary target for fractional reserves without being easily discovered.

It took the community 2 years to find first irregularities. It took another year to organise a "Monero run" on exchanges to proof the theory that most big exchanges were fractional. It's a fascinating read.

Shortly after the "Monero run" exchanges started to delist Monero which escalated in 2024 when almost all exchanges delisted it leading to a liquidity drain.

I challenge you to do a thought exercise.

What would happen to BTC price if all major custodians would go to only 10% fractional?

What would happen to BTC price if almost all CEX delisted BTC within one year?