The S&P 500 (-0.1%) began the week with a modest downtick to register its first decline in seven sessions. The Nasdaq Composite (-0.6%) underperformed while the Dow Jones Industrial Average (+0.2%) eked out a slim gain.

The new trading week was headlined by news from Vienna, where non-OPEC producers agreed to reduce their output by 558,000 barrels per day. In addition, a Saudi official indicated that his country may implement a larger cut than what was agreed to on November 30. Crude oil surged on the news, notching an overnight high near $54.50/bbl. The energy component pulled back throughout the day, ending its pit session with a 2.6% gain at $52.83/bbl.

Crude oil's surge gave a boost to the energy sector (+0.7%), but the group spent the day in a steady slide from its opening high after being up more than 2.0%. However, energy still fared better than the remaining five cyclical sectors, considering all five spent the day in negative territory.

The industrial sector (-0.4%) was pressured by defense contractors after President-elect Donald Trump criticized another defense contract he deemed excessive. Mr. Trump took aim at the F-35 program, sending shares of aircraft manufacturer Lockheed Martin (LMT 253.22, -6.30) lower by 2.4%. Most defense contractors retreated in sympathy with Lockheed Martin while Boeing (BA 157.16, +0.67) edged up to its record high. The Dow component has climbed 3.3% since being called out by Mr. Trump last Wednesday.

Similar to industrials, consumer discretionary (-0.8%), financials (-0.9%), and technology (-0.4%) spent the day in negative territory. Apparel retailers weighed on the discretionary space while the financial sector pulled back after last week's run. As for technology, the top-weighted group saw losses among large cap names and high-beta chipmakers. The PHLX Semiconductor Index lost 0.8% with Micron (MU 20.01, -0.49) falling 2.4% after the company warned that the memory market may be flooded by China within a few years.

The technology sector contributed to the relative weakness in the Nasdaq, but biotechnology also weighed on the tech-heavy index. The iShares Nasdaq Biotechnology ETF (IBB 267.53, -2.14) settled lower by 0.8% with Alexion Pharmaceuticals (ALXN 115.08, -16.99) diving 12.9% after two top executives resigned from the company.

Unlike biotechnology, the broader health care sector (+0.5%) held a modest gain throughout the session. Other countercyclical groups also displayed relative strength with telecom services (+1.1%) and utilities (+1.0%) ending in the lead.

Treasuries retreated overnight, but most of the losses were erased intraday, leaving the 10-yr yield higher by a basis point at 2.48%.

Investor participation was above average as nearly 1.2 billion shares changed hands at the NYSE floor.

Today's economic data was limited to the Treasury Budget statement for November, which showed a deficit of $137 billion while the Briefing.com consensus expected a deficit of $135 billion.

Tomorrow's economic data will be limited to the 8:30 ET release of November Import Prices ex-oil and Export Prices ex-agriculture.

Russell 2000 +21.5% YTD

Dow Jones Industrial Average +13.6% YTD

S&P 500 +10.4% YTD

Nasdaq Composite +8.1% YTD