The biggest US telephone operators, Verizon VZ.N and AT&T T.N , rose more than 2 percent, providing the second- and third-biggest individual stock boosts for the S&P.
The Dow Jones industrial average rose 17 points, or 0.1 percent, to 22,388. The Nasdaq Composite .IXIC dropped 5.28 points, or 0.08 percent, to 6,456.04, with Apple Inc AAPL.O as its biggest drag. Financials were also pressured, with the sub-index edging down 0.57 percent.
Investors are eagerly expecting the Federal Reserve to announce the first steps toward unwinding its $4.5 trillion balance sheet.
Back-to-back hurricanes that slammed into Texas and Florida - with Hurricane Jose still looming off the eastern United States seaboard and Hurricane Maria bearing down on Puerto Rico - also could influence Fed thinking about the timing of the next rate hike, though it is unclear in what direction. Household spending and business investment growth have both increased.
The euro was up 0.15 percent at 133.645 yen, recovering some of the losses suffered the previous day, when the common currency's slide against the dollar nudged it away from a 21-month high of 134.160 set on Tuesday.
"Donald Trump's comments overnight in regards to North Korea have certainly added a bid to the precious complex, but all in all very quiet ahead of the (Fed statement)", a trader told reports. Aside from the North Korean UN delegation walking out prior to Trump's address, there has been no reaction, yet, from Pyongyang. More recently, the North launched a missile that passed over Japan on September 15 local time. "Generally, people are not buying into gold because stock markets are higher". Toshiba indicated last week it had entered into a memorandum of understanding with Bain Capital, which backed a separate group bidding for the unit, over the sale.
Seven of the 11 major S&P sectors were higher, led by a 1.56 percent gain in the telecom services sector.
Meanwhile, traders have been speculating whether the European Central Bank is moving closer to wind down its 2.3 trillion euro asset purchase programme.
While the decision to shrink the Fed's balance sheet is much expected, when and how the Fed will manipulate its target for short-term interest rates is less clear.
In late-morning trades, the benchmark Nikkei 225 Index is advancing 144.07 points or 0.71 percent to 20,454.53, off a high of 20,481.27 in early trades.