The stock market kicked off the week with index-level gains that saw the S&P 500 (+0.5%) and Nasdaq Composite (+0.9%) secure new all-time intraday and closing highs, while the DJIA (+0.1%) lagged. Gains were largely concentrated in a select group of mega-cap leaders, which continued to flex their influence over index performance.

Shares of Tesla (TSLA 410.04, +14.10, +3.56%) surged early after it was reported that CEO Elon Musk purchased around 2.6 million shares of stock worth nearly $1 billion on Friday, his first open market purchase of the stock since February 2020. Though the stock finished well off its session highs, it still added substantial gains to its impressive September run and helped the consumer discretionary sector (+1.1%) finish among the best-performing S&P 500 sectors.

The communication services sector (+2.3%) comfortably outpaced all other sectors today as Alphabet (GOOG 251.76, +10.38, +4.30%) hit fresh records, becoming just the fourth U.S. company to surpass $3 trillion in market value.

With additional solid showings from Amazon (AMZN 231.43, +3.28, +1.44%), Meta Platforms (META 764.70, +9.11, +1.21%), and Microsoft (MSFT 515.36, +5.46, +1.07%), the Vanguard Mega Cap Growth ETF advanced 0.9% today. 

The information technology sector (+0.8%) traded flattish out of the gate, nursing a loss in NVIDIA (NVDA 177.75, -0.07, -0.04%), which traded lower following reports that China found the company to be in violation of its anti-monopoly law. The company issued a statement in response reaffirming their compliance with the law "in all respects," and the stock finished near its flatline. 

Elsewhere in the sector, Seagate Tech (STX 211.12, +15.13, +7.72%) and Western Digital (WDC 102.39, +4.73, +4.84%) furthered their strong recent runs as HDD prices continue to increase due to tight supply and strong demand for large-capacity drives fueled by AI-driven storage requirements.

The industrials (+0.5%) and utilities (+0.2%) sectors round out the five S&P 500 sectors that advanced today. 

Of the six sectors that finished lower, only the consumer staples (-1.2%), health care (-1.0%), and materials (-0.8%) finished with losses wider than 0.5%.

While today's action resulted in decent index level gains, the advance was dependent on the strong performances of several mega-cap names. The S&P 500 Equal Weighted Index (-0.2%) finished with a loss today, markedly underperforming the market-weighted S&P 500 (+0.5%). 

Today's gains came on lighter-than-average volume, reflecting a cautious tone as investors await this week's FOMC meeting for clarity on the policy path ahead.

With a 25-basis point rate cut already fully priced in, homebuilder stocks retreated in what looked like an early "sell-the-news" move, leaving the iShares U.S. Home Construction ETF down 1.3%.

Meanwhile, smaller-cap names delivered a mixed showing after their recent strength on firming rate cut expectations, with the Russell 2000 closing with a 0.3% gain while the S&P MidCap 400 slipped 0.1%.

On the trade front, the U.S. and China reached a framework agreement to transition TikTok to U.S. ownership, with a scheduled call between President Trump and Chinese President Xi Jinping on Friday to finalize discussions.

U.S. Treasuries began the week with gains across the curve. The 2-year note yield settled down three basis points to 3.53%, and the 10-year note yield settled down three basis points to 4.03%. 

• Nasdaq Composite: +15.7% YTD
• S&P 500: +12.5% YTD
• DJIA: +7.9% YTD
• Russell 2000: +7.9% YTD
• S&P Mid Cap 400: +5.1% YTD

Reviewing today's data:

• The Empire State Manufacturing survey fell to -8.7 in September (Briefing.com consensus 3.0) from 11.9 in August.