The New York Fed, which carries out the central bank's market operation, announced $2 billion in overnight repurchase agreements.
The Fed's "repo" follows a move by the Bank of Japan to put $5 billion into the markets and an addition by the European Central Bank of $65.3 billion; the ECB added more than $200 billion last week. The moves appeared to placate Wall Street for now and allowed it to focus on a week of fresh economic data.
Monday's injection, however, was smaller than normal, perhaps reassuring some investors that the central bank doesn't yet feel the need to pump more liquidity into the market.
The Dow Jones industrial average fell 3.01, or 0.02 percent, to 13,236.53.
Broader stock indicators also fell. The Standard & Poor's 500 index fell 0.72, or 0.05 percent, to 1,452.92, and the Nasdaq composite index retreated 2.65, or 0.10 percent, to 2,542.24.
After enduring sharp swings to the downside last week, the Dow and other major indexes ultimately finished the week with a modest gain.
Wall Street wasn't comfortable enough to hold positions overnight, and ultimately sold them off just before the closing bell Monday.
Light, sweet crude rose 13 cents to $71.60 per barrel on the New York Mercantile Exchange.