I think depending on the strength of our money, if we have stock of the bitcoin dominant than circulating in the market then we easily manipulate the price of the bitcoin.
The people that holds a lot of bitcoin can have the power to manipulate the price of it. And we know on how the whales are manipulating the market and there are pump and dump groups that are helping each other to get some decent profit. There is a way to manipulate bitcoins price but it is not that an easy thing if you only have very few.
I think big capital will still be difficult to use to manipulate bitcoin prices. If they do not have a good plan. One person is not enough to manipulate bitcoin prices