June 21 (Reuters) - U.S. stocks rose at the open on Monday as China's vow to allow a flexible yuan invigorated optimism in the global recovery and raised the outlook for sales in the long term at U.S. multinationals.

The Dow Jones industrial average .DJI gained 120.09 points, or 1.15 percent, to 10,570.73. The Standard & Poor's 500 Index .SPX rose 12.49 points, or 1.12 percent, to 1,130.00. The Nasdaq Composite Index .IXIC added 27.34 points, or 1.18 percent, to 2,337.14.

The S&P 500 briefly rose above 1,130.29, the midpoint between its 2010 high- and low-points, seen as a key technical resistance.

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