Recent gains at the index level have been driven mostly by tech stocks

The stock market's recent gains have been driven by a small handful of names.

The S&P 500's latest trip back to near-record territory has been powered by a surprisingly small number of stocks.

As of Tuesday's close, the S&P 500 SPX was only 0.44% shy of a record closing high, and yet 52% of individual member stocks were trading below their long-term 200-day moving averages. This is a reflection of the fact that a handful of stocks, chiefly hyperscalers like Meta (META) and semiconductor stocks like Micron Technology (MU), have been doing much of the heavy lifting lately.

According to Dow Jones Market Data, the last time there were that many S&P 500 components below their 200-day moving averages with the index within 1% of its record high was indeed March 27, 2000 - right around the dot-com bubble peak.

This has hardly been the first sign of bad stock-market breadth to crop up over the past few weeks. MarketWatch flagged another sign of weakness on Monday, noting that about 60% of the stocks in the S&P 500 down more than 20% from their all-time highs.

"I seem to come across a stat every day that we 'haven't seen since 2000,'" Jonathan Krinsky, a top technical strategist at BTIG, told MarketWatch via email.

In recent days, Krinsky has warned clients about what he sees as a growing triple threat: weak stock-market breadth, rising credit spreads and rising nominal Treasury yields.

"Those issues haven't gone away, and today we are finally starting to see some index deterioration," Krinsky said in written commentary shared on Tuesday. Stocks continued to slide on Wednesday, with the S&P 500 down 0.8% between Tuesday and Wednesday, FactSet data showed.

The Nasdaq Composite COMP on Wednesday tallied its biggest one-day point and percentage decline since Aug. 18, while the Dow Jones Industrial Average DJIA also tallied a second straight day of losses.

-Joseph Adinolfi