U.S. stocks rose slightly on Monday as the U.S. dollar hit a 1-year low against the euro ahead of the start of a Federal Reserve policy meeting, boosting oil and metals prices.

Crude oil futures rose 2 percent to $71.10 per barrel, and copper for three-month delivery rose 1.2 percent.

U.S. Steel Corp rose 3.4 percent to $49.63 as metal prices advanced and after Bank of America-Merrill Lynch upgraded U.S. Steel's shares to neutral from underperform.

Positive comments from Citigroup lifted shares of Peabody Energy Corp and Massey Energy , leaders by percentage gain on the S&P energy index <.GSPE>.

The Federal Reserve is set to start its two-day monetary policy meeting on Tuesday with a decision on interest rates due at around 2:15 p.m. (1815 GMT) the following day.

The euro reached a one-year high against the U.S. dollar as dealers took advantage of the greenback's gains the previous session to resume selling ahead of the Fed meeting and a Group of 20 nations summit later in the week. The dollar index <.DXY> tumbled 0.9 percent.

The asset classes are so incredibly correlated right now. When the dollar (falls) you are going to see the stock market come in and some commodities come in, said Tom Alexander, head of Alexander Trading in Savannah, Georgia.

It is an asset allocation play and has nothing to do with traditional financial metrics. The market itself is a commodity, he said.

Financials gave stocks a boost as Bank of America Corp shares rose 1.9 percent after an analyst upgrade while Citigroup Inc gained 3.8 percent.

The Government of Singapore Investment Corp (GIC) said it halved its stake in Citi through open market sales to below 5 percent. An analyst said the post facto announcement eased selling pressures on Citi stock.

The Dow Jones industrial average <.DJI> gained 8.99 points, or 0.09 percent, to 9,787.85. The Standard & Poor's 500 Index <.SPX> rose 3.88 points, or 0.36 percent, to 1,068.54. The Nasdaq Composite Index <.IXIC> added 4.31 points, or 0.20 percent, to 2,142.35.

Macy's Inc shares jumped rose 6 percent to $18.85 after Citigroup upgraded the company to buy.

Declining stocks included health insurers, which limited gains on the S&P 500. The S&P managed health care sub index <.GSPHMO> fell 2.2 percent, weighed by declines in UnitedHealth Group , down 2.9 percent to $27.76 and Cigna Corp , which fell 2.2 percent to $31.06.