Stock investors better hope the oil price plunge stabilizes

Oil is down more than 8 percent so far this week and it's no coincidence to see the struggle as well. History shows the stock market rarely finishes higher during a week when crude prices decline significantly.

Using Kensho, we found more than 100 five-day periods in the last decade when WTI crude declined by 5 percent or more. Here's the average performance of the S&P 500 and other relevant securities during those five-day periods: