The stock market opened the week with a win, but concerns over heightened geopolitical tensions held gains in check throughout the session. The S&P 500 and the Nasdaq settled with slim gains of 0.1% apiece, while the Dow finished flat.

Investors started the day with optimism, moving the major averages modestly higher, but there was no doubt that last week's missile strike in Syria weighed on the positive sentiment. In addition, the U.S. Navy ordered the Carl Vinson Strike group to begin moving towards the Korean peninsula over the weekend. With those concerns playing in the background, the stock market dipped into negative territory around midday on rumors that China deployed about 150,000 troops in two groups to its border with North Korea. Equities recovered shortly thereafter, but never quite made it back to their best levels of the day.

This rumor of Chinese troop movement has been gaining traction with Asian media in recent days, and it has been noticed by U.S. investors during an abbreviated week, which is likely to see reduced participation. That was the case on Monday with only 794.0 million shares changing hands at the NYSE floor (200-day average: 970.8 million).

For sector standings, the energy group (+0.8%) finished atop the day's leaderboard thanks to a solid performance from crude oil. The commodity finished 1.6% higher at $53.06/bbl following further production complications in Libya. The country's largest oilfield was shut down on Sunday after a group blocked a pipeline linking it to an oil terminal.

The consumer discretionary (+0.4%), industrials (+0.2%), consumer staples (+0.3%), real estate (+0.7%), and utilities (+0.2%) sectors also outperformed the broader market. Retailers helped the consumer discretionary sector in its advance, evidenced by the 1.5% increase in the SPDR S&P Retail ETF (XRT 42.11, +0.60). One of the XRT's top-performers was Amazon (AMZN 907.04, +12.16), which added 1.4% in another solid performance.

On the flip side, the financials (-0.3%) and telecom services (-0.3%) groups settled at the bottom of the day's leaderboard while the health care (-0.2%) and technology (-0.2%) groups performed only modestly better. The top-weighted technology sector suffered from a lackluster performance from its top component by market cap, Apple (AAPL 143.14, -0.20), and selling pressure within the semiconductor industry; the PHLX Semiconductor Index closed lower by 0.8%.

In the Treasury market, the main event, Fed Chair Janet Yellen's speech at the University of Michigan, has yet to occur. Ms. Yellen will participate in a question-and-answer session with the public shortly at 16:10 ET. The benchmark 10-yr yield settled two basis points lower at 2.36%.

Investors did not receive any economic data on Monday. The first report of the week--February JOLTS--will cross the wires tomorrow at 10:00 ET.

Nasdaq Composite +9.3% YTD

S&P 500 +5.3% YTD

Dow Jones Industrial Average +4.5% YTD

Russell 2000 +0.7% YTD