- The Fed kept interest rates unchanged, as was widely expected.
- Investors also focused on corporate quarterly results.
U.S. stocks closed mostly higher on the back of strong earnings and following the Federal Reserve's decision to keep interest rates unchanged.
The Dow Jones industrial average rose 97.58 points to close at 21,711.01 and hit intraday and closing records. Boeing rose 9.88 percent and contributed the most gains on the 30-stock index. The hit an intraday record before closing flat at 2,477.83. The Nasdaq composite climbed 0.16 percent to 6,422.75 and also notched all-time highs.
The Fed was widely expected to keep monetary policy steady. The central bank, however, laid the groundwork for winding down its massive stimulus program in September.
"The Fed is entering a yield-curve management program if you will," said David Schiegoleit, managing director of investments at U.S Bank Private Client Reserve. "By reducing the balance sheet, the Fed is effectively steepening the yield curve."
They said they plan to start the unwinding "relatively soon," which is the crux of the statement. Fed watchers had been looking for the language to change from "this year," as indicated following the June meeting, to something more immediate.
The central bank also said, however, inflation remains below its 2 percent target.
"I think they were giving themselves some wiggle room," said Chuck Cumello, president and CEO of Essex Financial. "They don't want to overshoot."
U.S. Treasury yields fell heading into the Fed's announcement and remained at similar levels afterward. The 10-year yield traded at 2.3 percent while the two-year yield held around 1.363 percent.
The CBOE Volatility Index (VIX), widely considered the best gauge of fear in the market, traded at a record low, breaking below 9, shortly after the Fed released its statement.
"They were not aggressive in their inflation assessment but acknowledged that inflation is running below 2 percent," said Robert Tipp, chief investment strategist at PGIM Fixed Income. "But this is not a Fed that thinks it's behind the curve and that there is still time to normalize monetary policy."
Investors also focused on corporate quarterly results. Dow-component Boeing posted earnings per share of $2.55, topping Wall Street estimates. The company's sales came in below expectations but the firm raised its full-year earnings guidance to a range of $9.80 to $10 per share.
Coca-Cola and Ford also posted better-than-expected quarterly results.
Earnings season has been strong thus far. With 34 percent of S&P 500 components having reported as of Wednesday morning, 78 percent have beaten expectations on the bottom line and 73 percent have topped on sales, according to data from The Earnings Scout.
Kim Forrest, senior equity analyst at Fort Pitt Capital, said she expects companies to continue reporting strong quarterly results this season. "The results are showing the economy continues to improve, so I would expect these types of results to continue."
Equities came into Wednesday's session having posted solid gains on Tuesday. The S&P and the Nasdaq posted record intraday and closing highs.
"We have seen phenomenal earnings growth right now. Analysts are forecasting a continuation of that. So, I don't know what is driving earnings," Nobel Prize-winning economist Robert Shiller told CNBC. "I would be skeptical that they would continue at such a blistering pace. History shows that big earnings increases like this have a tendency to revert to trend."
In economic news, mortgage applications rose just 0.4 percent seasonally adjusted compared with the previous week. New home sales rose 0.8 percent in June.
In commodities, U.S. crude for September delivery rose 1.8 percent to settle at $48.75 a barrel after the Energy Information Administration reported a crude drawdown of 7.2 million barrels.
—CNBC's Stephanie Landsman and Jeff Cox contributed to this report.