As expected, the Fed lifted interest rates for the second time this year, and in a post-meeting press conference, Fed Chair Janet Yellen said the economy is on the path to achieving the current 2% inflation target.
Investors will also be looking for any details on the Fed's plans to trim its $4.5 trillion balance sheet in the face of improving economic conditions.
"With the weak data, you start to wonder why the Fed is so bent on raising rate".
The S&P 500 Index (SPX - 2,432.46) closed down 5.5 points, or 0.2%, while the Nasdaq Composite (COMP - 6,165.50) gave up 29.4 points, or 0.5%.
Mattel slumped 6.7 percent, falling for a second straight session after the company unveiled a turnaround strategy that included a big cut to the dividend to finance technology investment initiatives. However, defensive sectors such as utilities rose.
After a record close yesterday, the Dow Jones Industrial Average (DJIA) dropped more than 100 points out of the gate, but stemmed its losses by the close.
A gunman opened fire on Republican members of Congress during a baseball practice near Washington on Wednesday, wounding several people including House of Representatives Majority Whip Steve Scalise, according to police and media reports. The VIX Volatility Index was higher for the day at 10.90 for a gain of 0.26 points or 2.44%.
Exxon and Chevron were the top drags on the S&P and the Dow.
The S&P 600 Small-Cap Index closed at 856.96 for a loss of 4.19 points or 0.49%.
Kroger Co (KR) was the top decliner on the S&P 500, falling by almost 12%.
Declining issues outnumbered advancers on the NYSE by 1,499 to 1,293. On the Nasdaq, 1,345 issues fell and 979 advanced.