June 10 (Reuters) - All three major U.S. stock indexes were down more than 1% on Wednesday afternoon, with chipmaker shares extending recent declines and with renewed tensions between the U.S. and Iran adding to investor uncertainty.

 President Donald Trump said the U.S. would attack Iran again "very hard" following one of the most significant exchanges of fire overnight since an April ceasefire in the Middle East war. 

An index of semiconductors was down 2.6%. Nvidia and Broadcom ( AVGO ) were among the biggest drags on the S&P 500, while the S&P 500 tech index was down 1.1%. Investors have been worried about stretched valuations in the sector.

The Cboe Volatility Index added to Tuesday's advance, with volatility picking up in recent days.

Investors were still taking some profits in the tech space, said Tom Hainlin, an investment strategist at U.S. Bank Wealth Management in Minneapolis.

Also, investors are now "pricing in maybe a higher interest rate" after recent economic data and are also worried about the war, he said.

"Perhaps that conflict continues on into the mid to late summer," he said. 

The Federal Reserve is widely expected to hold interest rates at its June policy meeting. Investors are pricing in at least one 25-basis-point rate hike by the end of the year. 

The Dow Jones Industrial Average fell 721.32 points, or 1.42%, to 50,150.79, the S&P 500 lost 87.78 points, or 1.19%, to 7,298.87 and the Nasdaq Composite lost 382.36 points, or 1.49%, to 25,296.35.

Friday's U.S. jobs report was stronger than expected. On Wednesday, U.S. consumer prices increased 4.2% in the 12 months through May, the largest gain since April 2023, data showed, as the Middle East conflict raised the price of gasoline and other energy products.

The pace of increase was, however, in line with forecasts, as per a Reuters poll of economists.

Among other decliners, Super Micro Computer ( SMCI ) tumbled 20.9% after it announced plans to raise $7 billion through a series of equity and equity-linked financing transactions to fund component purchases for its growing AI server demand.

The rotation out of highly subscribed technology shares has aided other areas of the markets that have lagged this year, including healthcare, real estate and consumer staples. 

The much-hyped $1.75 trillion listing of SpaceX on Friday, targeting a record $75 billion raise, could also pressure U.S. stocks as concerns mount over excessive optimism in the tech sector.

Among other movers, shares of trucking companies XPO, J.B. Hunt and Old Dominion also dipped after Amazon announced expansion of its less-than-truckload freight services in the U.S. Industrials led declines among sectors.

Declining issues outnumbered advancers by a 1.41-to-1 ratio on the NYSE. There were 168 new highs and 103 new lows on the NYSE. On the Nasdaq, 2,038 stocks rose and 2,729 fell as declining issues outnumbered advancers by a 1.34-to-1 ratio.