The options market is more concerned about a potentially big move in the S&P 500 Index

Federal Reserve’s interest-rate decision Wednesday than it’s been at any point in almost a year.

The benchmark index is implied to move 0.95% on Wednesday, 

when the Fed gives its view on rates and Chair Jerome Powell holds his post-

meeting press conference, according to an options strategy known as an at-the-money straddle

where traders buy an equal number of calls and puts with the same strike price and expiration.