The Fed is not expected to raise interest rates at the two-day meeting, which begins on Tuesday, but investors will be on the lookout for clues about future hikes.
"If investors are inclined to make a bet, then they're better served by waiting a few days," said Jack Ablin, chief investment officer at BMO Private Bank in Chicago.
Global oil prices fell as much as 4 percent on concerns a six-week market recovery has gone beyond fundamentals.
The recent rally in oil prices and data pointing to a strengthening U.S. economy have helped stocks recover from a steep selloff at the start of the year.
The S&P 500 is now down about 1 percent in 2016, after having been down as much as 10.5 percent in mid-February.
As they also wait on the release of economic data, including U.S. retail sales, investors were further digesting moves by the European Central Bank and other global economic news last week.
"To me, it's one of those days where the market is doing its best to digest some of those factors and to see what's next," said Steven Baffico, chief executive officer at Four Wood Capital Partners in New York.
The Dow Jones industrial average <.DJI> closed up 15.82 points, or 0.09 percent, to 17,229.13, the S&P 500 <.SPX> lost 2.55 points, or 0.13 percent, to 2,019.64 and the Nasdaq Composite <.IXIC> added 1.81 points, or 0.04 percent, to 4,750.28.
Seven of the 10 major S&P sectors were lower. The energy sector <.SPNY> fell 0.6 percent. Schlumberger's (>> Schlumberger Limited.) 2.1-percent fall and Baker Hughes' (>> Baker Hughes Incorporated) 4.2-percent decline weighed the most on the sector.
The consumer discretionary sector <.SPLRCD> rose 0.4 percent.
McDonald's (>> McDonald's Corporation) and Boeing (>> Boeing Co) gave the biggest boosts to the Dow.
Starwood Hotels & Resorts (>> Starwood Hotels & Resorts Worldwide Inc) climbed 7.8 percent at $75.93 after the hotel operator received a takeover offer of $76 per share from a consortium of companies. Marriott (>> Marriott International Inc), which had been set to take over Starwood, ended up 3 percent at $70.93.
GW Pharmaceuticals
Shares of specialty grocery retailer Fresh Market Inc (>> The Fresh Market Inc) jumped 23.5 pct to $28.39 after it agreed to be acquired by private equity firm Apollo Global Management LLC (>> Apollo Global Management LLC).
About 6.3 billion shares changed hands in U.S. exchanges, below the 8.3 billion average over the last 20 sessions and the lowest daily volume of the year.
Declining issues outnumbered advancing ones on the NYSE by 1,679 to 1,311, for a 1.28-to-1 ratio on the downside; on the Nasdaq, 1,507 issues fell and 1,276 advanced for a 1.18-to-1 ratio favoring decliners.
The S&P 500 posted 12 new 52-week highs and no new lows; the Nasdaq recorded 40 new highs and 20 new lows.
(Additional reporting by Abhiram Nandakumar in Bengaluru; Editing by Meredith Mazzilli and Nick Zieminski)
By Laila Kearney
