(CNBC) U.S. stocks closed Thursday's trading session lower as a lack of resolution on Greece debt talks and declining transports weighed on investor sentiment.
The Dow transports resumed their decline, falling 0.91 percent. U.S. stocks have alternated between losses and gains in the last three trading days.
"Airlines have taken a major hit this month because of the overcapacity situation," said Howard Silverblatt, senior index analyst at S&P Dow Jones Funds.
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