Nasdaq’s Record Run Underscores Broader Confidence in Tech-Heavy Index

The Nasdaq Composite (COMP) jumped 2.3% on Monday, Sept. 21, its biggest one-day gain in seven weeks, and closed at a record high. It added 0.5% on Tuesday to set another record, while the S&P 500 (SPX) ended with a fractional loss. Monday's close was the index's 21st record of 2026 but the first since early June, according to Dow Jones Market Data.

The question for investors after a run like this is whether a new high leaves less room ahead. Historical data compiled by Bespoke Investment Group, cited by MarketWatch, points the other way.

What the historical data shows

Bespoke looked at past occasions when the Nasdaq rose more than 2% in a single day to a new peak. After those days, the index went on to deliver stronger-than-average returns over several time frames. One month later, it was up 3.7% on average, and gains were also above average over the following three months, six months and one year.

The data describes what has tended to happen, not a forecast for this rally. Tuesday's additional record is consistent with the pattern so far, but one session says little about the months ahead.

Why some strategists see support beyond the chart

Analysts also point to fundamentals behind the move.

The first is artificial intelligence. Mona Mahajan, head of investment strategy at Edward Jones, said in a phone interview on Tuesday that the AI trade, which has driven the latest push higher in tech stocks, will probably have "some legs through next year" because of heavy spending on infrastructure for the AI buildout. She added that the broader market stands to benefit as AI spreads beyond the companies building it and lifts productivity.

The second is monetary policy. The Federal Reserve raised its policy rate in September. Mahajan described the move as part of mid-cycle adjustments rather than the start of an aggressive series of hikes, and said it could even prove positive for stocks.

The third is growth. The Atlanta Fed's GDPNow tracker estimated third-quarter real GDP growth at an annualized 5.1%, up from 1.5% in the second quarter. Mahajan said stocks may keep rising on corporate profit growth and economic expansion.

The counterpoints

Not every signal is supportive. MarketWatch noted two concerns about the latest rally. One is breadth: a relatively small share of stocks has been participating in the gains, so the advance rests on fewer companies. The other is the rise in interest rates, which raises the rate used to discount future earnings and tends to weigh on stock valuations, especially for growth companies whose profits lie further out.

Third-quarter earnings as the next test

Third-quarter earnings reports, due in the coming weeks, are the next test. Yardeni Research said in a note that "investors have been watching analysts raising their earnings expectations faster than stock prices have been rising." When estimates climb faster than prices, valuations based on forward earnings come down, and Yardeni said that could lead investors to rethink valuations for some of the larger technology names, semiconductor stocks in particular.

Other items to follow:

• Whether the Nasdaq's gains broaden to more stocks, or stay concentrated in AI-linked leaders.
• The next GDPNow updates and the official third-quarter GDP estimate, measured against the 5.1% tracker reading.
• Fed communication on whether September's rate hike is a one-off adjustment or the start of a longer series.