A punishing rout in the oil market could portend a healthy bounce for stocks and crude futures if historical trends hold.

Brent and U.S. crude futures have recently tumbled more than $20 a barrel from four-year highs, plunging into a bear market over the course of six weeks. The pullback dovetailed with a broader sell-off in markets, a surge in global oil supplies and darkening forecasts for demand.

But investment firm Jefferies says there may be a silver lining to the clouds that have descended over the oil market.

"Severe one month declines in the price of oil has not presaged market weakness, quite the contrary, actually," the firm wrote in a research note Sunday.

"Historically, at least, rapid declines in the price of oil have tended to be bullish for the S&P even if it's often easy to spin oil price declines as a negative."

Jefferies researched what happens to stocks and crude futures after a move of two standard deviations to the downside over the course of a month for oil prices.