This year's stock market rally has been led by just a few large tech names — but that might not be such a bad thing.

Yahoo Finance's Josh Schafer has the scoop:

"We see a small group of tech winners leading stock gains as a feature of the artificial intelligence (AI) theme — not a flaw," Jean Boivin, head of BlackRock Investment Institute, wrote in a research note on Monday. "We stay overweight U.S. stocks."

AI darling Nvidia (NVDA) has accounted for nearly one-third of the S&P 500's gains this year, and outperformance in quarterly results from large-cap tech continues to be a reason why earnings for the S&P 500 are growing year over year.

As of Monday's close, Apple (AAPL), Alphabet (GOOG, GOOGL), Microsoft (MSFT), Amazon (AMZN), Meta (META), and Broadcom (AVGO) had also contributed more than a quarter of the major index's gains.

One potential concern is that the market could be at risk if a few large tech companies that have driven a lion's share of the gains stop surprising to the upside.

However, research from Morgan Stanley's chief investment officer, Mike Wilson, shows this might not be an issue.

Wilson found roughly 20% of the top 500 stocks are outperforming the broader index over a rolling one-month period. This is the lowest percentage of companies outperforming in Wilson's dataset dating back to 1965.

Wilson's work noted that after similar narrow breadth readings where less than 35% of companies are outperforming the index on a one-month basis, the S&P 500 rose about 4% on average over the next six months.

"Narrow breadth can persist but it's not necessarily a headwind to forward returns in and of itself," Wilson said. "We believe broadening is likely to be limited to high quality/large cap pockets for now."

Wilson argued that when considering the impact of high interest rates on corporations, this makes sense. Investors have flooded large-market-cap stocks that have held up well in the higher rate environment and are seeing earnings grow more than their smaller peers.

And a slew of recent upgrades to year-end S&P 500 targets reflect similar sentiment. Three Wall Street firms cited tech outperformance as part of the reason the index is doing better than they initially thought this year.