Stocks started the week on a weaker note, with an afternoon surge in oil prices adding to selling pressure that had already been evident across much of the broader market. The S&P 500 (-0.5%), Nasdaq Composite (-0.3%), and DJIA (-0.5%) all finished lower, while strength in semiconductor stocks helped limit the Nasdaq's decline.

The market had already displayed a negative bias beneath the surface during the morning, but losses widened as geopolitical concerns pushed oil prices higher in the afternoon. President Trump told reporters that he does not think Iran will agree to the deal he views as necessary ahead of today's expiration of the 60-day ceasefire agreement between the U.S. and Iran. WTI crude oil futures settled $2.06 higher (+2.5%) at $84.46 per barrel.

The late climb in oil left the energy sector (+0.9%) as the only S&P 500 sector to finish higher and overshadowed what had been a strong showing from semiconductor stocks earlier in the session. The PHLX Semiconductor Index (+1.6%) still outperformed considerably, though it surrendered a sizable portion of an earlier gain that had topped 2.5%. Memory stocks remained a bright spot, with Sandisk (SNDK 1786.85, +145.74, +8.88%) extending its recent surge after Commerce Secretary Howard Lutnick said the Trump administration does not want Apple (AAPL 305.59, -0.34, -0.11%) purchasing Chinese memory chips. Applied Materials (AMAT 535.31, +28.13, +5.55%) also rebounded sharply after moving lower on Friday despite delivering a strong beat-and-raise earnings report.

The fading semiconductor rally, combined with weakness across other large technology names, ultimately pulled the information technology sector (-0.2%) into negative territory. Continued enthusiasm surrounding the AI trade provided some support after Anthropic reported a massive jump in revenue, while outside the sector, SpaceX (SPCX 146.23, +6.23, +4.45%) extended its recovery from post-IPO lows following regulatory filings showing newly disclosed positions from NVIDIA (NVDA 225.01, -0.15, -0.07%) and Advanced Micro Devices (AMD 506.00, -8.39, -1.63%).

Weakness remained broad elsewhere. The communication services sector (-1.5%) was among the worst performers as Meta Platforms (META 568.97, -20.88, -3.54%) remained under pressure ahead of opening arguments Tuesday in a child social-media addiction case.

The consumer staples sector (-1.5%) matched that loss amid weakness in alcoholic beverage names. The consumer discretionary (-1.0%) and financials (-1.0%) sectors also lagged. Apparel and homebuilder stocks weighed on consumer discretionary, with NIKE (NKE 39.09, -1.64, -4.03%) falling to its lowest level since late 2014. Homebuilders faced an additional headwind from elevated longer-term Treasury yields after the 30-year yield reached a fresh 19-year high during the session.

The weakness extended beyond the large-cap benchmarks, with the Russell 2000 (-0.4%) and S&P MidCap 400 (-0.3%) also finishing lower.

Monday's session ultimately highlighted the market's inability to capitalize on another strong showing from semiconductor and AI-related stocks. Chip strength provided an important counterweight through much of the day, but broad sector weakness and the afternoon jump in oil prices as the U.S.-Iran ceasefire expired proved too much to overcome, leaving the major averages near their lows at the close.

U.S. Treasuries began the week with steady selling in longer tenors, driving the 30-year note yield to a fresh high for the year while the front end resisted, but also eventually gave in to the pressure. The 2-year note yield settled up one basis point to 4.18%, the 10-year note yield settled up three basis points to 4.72%, and the 30-year note yield settled up four basis points to 5.31%. 

• Russell 2000: +23.2% YTD
• S&P Mid Cap 400: +18.5% YTD
• Nasdaq Composite: +14.6% YTD
• S&p 500: +13.1% YTD
• DJIA: +11.2% YTD

Reviewing today's data:

• August Empire State Manufacturing 20.6 (Briefing.com consensus 11.0); Prior 15.6
• August NAHB Housing Market Index 35 (Briefing.com consensus 34); Prior 34