You shouldn't be worrying about large scale investors taking positions into Bitcoin, it's already happening. No one would ever just dump insane amounts of funds into something, which obviously will only result in the market to soar badly. It's a long term process where they accumulate as many coins as possible, but without bumping up the market up too much. Great way for them to avoid bumping the market when it comes to accumulating through exchanges, is that they buy their coins off-exchange (OTC). It allows them to buy a large number of coins at a fixed price, which means that it isn't only cheaper, but it also doesn't affect the exchange rates in any way. Multi million trades are happening on a very regular basis, but without us noticing anything.