I presume large volume and large body candlesticks are institutional selling or buying. Why would institutional investors sell a stock when it does not fall below the lowest level since the day it listed?

This stock was listed in SG 15 years ago and didn't drop below the lowest, so it couldn't be bought lower than the lowest price since listed. Is this true? Or can institutional investors go short?

Pardon my ignorance.

Thank you in advance