The stock market was broadly lower on Friday, with the Dow Jones Industrial Average (DJINDICES:^DJI) down 0.13% at 12:05 p.m. EDT. The tech-heavy Nasdaq Composite was the worst performer among the major indexes, hurt by an analyst warning about tech stock valuations.

That warning pertained to Dow components Apple (NASDAQ:AAPL) and Microsoft (NASDAQ:MSFT), which are trading at historically high valuations after months-long rallies. Both stocks slumped on Friday, as did shares of Home Depot (NYSE:HD) following a separate analyst warning.

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Barclays warns about big tech valuations

Mega-technology stocks like Apple and Microsoft have led the way since the market bottomed out earlier this year in the throes of the COVID-19 pandemic. Shares of Apple are up around 46% year to date, while shares of Microsoft have gained roughly 26% in the same timeframe.

This rally in tech stocks has pushed valuations to historically high levels.