A way to avoid this is to not buy the indexes themselves but deeper capitalization based funds like VTI etc. This is still basically an index fund but since it buys past the "500" it avoids this BS.
Why would you want to avoid it? Either VTI is a better investment (for your profile, of course) than the S&P 500 and such or it isn't; it doesn't really matter if it's because of "index frontrunning" or any other factor.
