Hedge funds buy baskets of stocks when doing so looks good to their models/ algos. The Fed is not allowed to buy stocks, they are allowed to buy government securities in open market operations in order to achieve the target rate for the federal funds rate. The guidelines for this are explained in the Section 14 of the Federal Reserve Act. You can find the Fed holdings in the Federal Reserve Statistics I like that you are trying to think things out, though. Posting your thoughts is a good way to learn, if you keep an open mind and research the better replies to your posts.
The Fed official with the brainstorm for saving the stock market in times of emergency was former Fed governor Robert Heller. In a speech he gave shortly after leaving the Fed in 1989, Heller said that so-called circuit breakers would not be enough to stop an accident in the financial markets. Under emergency circumstances, Heller said the Federal Reserve should become the buyer of last resort by directly purchasing stock futures contracts in an effort to prop up Wall Street.
SPX has a market cap of $38.2 trillion. How much money is invested in SPX futures contracts right now ? From August 6, 2014 : Did this ridiculous opinion of yours help you trade better ?
"Talking about stock market disturbances, Heller said that the circuit breakers now in place to calm disruptive markets may not be effective because they allow imbalances of sell orders to accumulate. Circuit breakers put a clamp on program trading once the Dow is down at least 50 points." Clues you in to just how old the article is *cough29yearscough*
I think I missed one very important point: even if the future can be manipulated, the short term trend of the stock will be affected, but the long term trend will not, as the future has the Due date settlement based on the stock market price.