Well it depends on what their bitcoins are doing to those institutions. We had auctions for recovered stolen coins a while back and everyone speculated about what would happen if those large quantities of coins were to enter the market again. We now know that the coins went to the owner who had the coins hoarded, and the price remained stable.

If the owner decided to see all the coins at the same time, the price would have taken a nose dive because of a sudden injection into the supply side of large quantities of coins. It was going to send the markets into a frenzy. This will seen by speculators as a dump and will cause other individual selling their coins to have a trigger effect.

For those institutional buyers, the same goes, if one of them dumps coins worth trillions of dollars into exchanges. Then the price will collapse.(causing volatility a lot)