It is the case that some assets in the top twenty can be 'staked'. This generally refers to a process whereby they are put to work, in some way, to assist with maintaining or supporting blockchain ecosytems. Staking generates additional income for the fund, as payouts are received in native assets. These assets are entirely reinvested i.e. they are dealt with in accordance with the fund rules.
It should be noted that generating significant returns from staking is often impossible for the average investor. For example, 1000 DASH is required for a masternode. This constitutes an additional stream of revenue for token holders.
Currently, NEO, DASH and XLM are being staked. These returns are disclosed in quarterly reports.