There are certain indexes that are effected by lower crude.
The Nasdaq is not really effected by crude, but its effected by the TNX.
The Dow Industrials is effected by the price of crude, well, because they are industrials.
Airlines are effected by crude.
The S&P 500 is a mixed bag. Some of its components are more effected then others. Dont forget that there are companies like Exxon in the S&P which would stand to increase by higher oil prices.
Each company and index has its own properties. Each case has to be examined carefully.
If the truth be known, the only thing holding up the S&P 500 today is the fact that oil did not go through the support. Companies like Exxon are rallying. Hopefully, not on a dead cat bounce because I do have some energy positions. If oil did break the support, then the S&P would tank below resistance.