Share your insights or perspective on the financial matter presented in the input.

How much do big firms and investors affect the stock market?
It's not either or.  Much of the time the value of the stock has some tangible relation to the financial prospects of the company. The value of Ford and GM stock rose when they were selling a lot of cars, and collapsed when their cars became unpopular. Other companies (Enron for example) frankly 'cook the books' to make it appear they are prospering, when they are actually drowning in debt and non-performing assets. So called "penny stocks" have both low prices and low volumes and are susceptible to "pump and dump" schemes, where a manipulator buys a bunch of the stock, touts the stock to the world, pointing to the recent increase in price. They then sell out to all the new buyers, and the price collapses.  If you are going to invest in the stock market it's up to you to figure out which companies are which.