The U.S. options market is showing increasing investor concern about a stock-market sell-off next year, driven at least partially by the looming presidential election, according to Goldman Sachs Group Inc.

“As investors consider the outcome of the election, the distribution of S&P 500 levels implied by the options market at year-end is wide,” strategists including David Kostin wrote in a note Monday.

While options pricing currently implies a 22% probability the S&P 500 ends next year above 3,400 -- an 8% gain -- it also shows a 28% chance the index finishes below 2,600, a 17% slump, they said.

A gauge of demand for downside protection known as skew, which rises when bearish put options become more expensive than bullish calls, has climbed above its historical average for one-year maturities, according to data compiled by Bloomberg.

Recent weeks have seen a number of prominent investors including Paul Tudor Jones and Leon Cooperman warning of the risk of a market sell-off should Democrat Elizabeth Warren or Bernie Sanders emerge victorious. Such predictions tend not to have a good track record and others such as RBC Capital Markets think the concerns are overdone.

Goldman said it is making no prediction on the outcome of the presidential race, and Kostin has a target of 3,400 for the benchmark U.S. stock gauge by the end of next year.

Option skew over different maturities suggests investors are more worried about the run-up to the election than its aftermath, with the measure higher for September and October than for November and December, Goldman said.

“This likely reflects investors positioning for a post-election relief rally once November uncertainty has been resolved,” the strategists wrote.