Institutional investors can be one of the most welcome things a company can ask for. It is rare to have institutional investors in penny stocks for one, much less pinkies, but rather more commonly seen in bigger board stocks, where these types of buyers feel more secure in their investments. The benefit they add as shareholders is that they tie up shares from the float (if bought from the open market) for long periods of time. Usually, until they've realized a very handsome ROI.
They can also be valuable to have, as they tend to offer assistance in various forms, depending on the type of investors they are.
Conversely, I believe they have been known to short their own positions to further their positions in the company, at even lower levels than originally entered. This, I don't believe is quite so common though.
(This is the extent of my knowledge of institutional investing. As much as this may be, I welcome any additional comments others may have.)