Pay out a percentage of staking rewards to depositors of POS coins. This would allow customers to "hold" the coins and reap staking rewards while simultaneously setting limit orders in case of a price increase.
I'm not aware of any exchange that does this -- and maybe there's good reason for that. I haven't thought through all the logistics.
Binance does that for few coins/tokens, It would be nice if they did it for all the POS coins. Coinbase has started staking service for Tezos and they might add more like it. I personally like staking by myself for the obvious reasons.