Is there a study out there which tested if Apple's stock and other S&P500 stocks are pushed ever higher by all this money pouring into unmanaged ETF indexes? E.

Is there a study out there which tested if Apple's stock and other S&P500 stocks are pushed ever higher by all this money pouring into unmanaged ETF indexes? E.g. if you buy an S&P500 index-tracking ETF you automatically buy a bunch of Apple shares too. This might mean that the trend of buying ETFs will help Apple stock price staying high.