What are some individual stocks that closely trace the S&P 500 that aren't ETFs?

I want to be able to see, in theory, how the S&P is performing post-market and pre-market, but neither .INX nor any of the ETFs show any after hours info.

Submitted May 01, 2017 at 12:29AM by jball037 http://ift.tt/2plFnSX