Fundamentally many things have changed, Bonds breaking higher, Interest rates etc. The derivative market.
I think this correction is going deeper than what many believe.
I was analysing the Dow and S$p yesterday before the market opening this is what i wrote to a fellow trader, "Just gone through the Dow , S&P and some of the Russel. Thinking could be another test lower before a continuation." I am monitoring good setups, but holding back from buying at the moment, cause most likely need a double bottom or consolidation.
I've posted a 101 on intermarket relationships.
This was a bit of a kicker last night also.
https://www.cnbc.com/2018/02/08/bank-of-england-policymakers-interest-rates-unchanged.html
I don't like to copy and paste opinions, however, at present, I think the above two links explains alot for people who don't understand the mechanic's of the markets.