I would think PayPal is way down the list of largest Bitcoin “holders”...the Coinbase commercial exchange does far more BTC business than PayPal, and would have to have more on hand. Then there are the the private & anonymous “whales” like Satoshi N. (BTC inventor)...he is estimated to have 11 million BTC ($669 Billion) on hand.
More info.:
https://usethebitcoin.com/top-10-richest-bitcoin-owners/
Make that 1.1 million BTC for Satoshi N. in my prior post...11 million is waaaay too many!! ;-) Sorry about that!