(For a live blog on the U.S. stock market, click or type LIVE/ in an Eikon news window)
* Weak Texas Instruments, STMicro forecasts hit chipmakers
* AT&T's weak TV results hits stock, other media companies
* Boeing rises after lifting FY profit forecast
* Microsoft, AMD, Ford drop ahead of results after the bell
* Indexes down: Dow 0.39 pct, S&P 0.90 pct, Nasdaq 1.50 pct (Updates prices to afternoon, changes comment)
By Amy Caren Daniel
Oct 24 (Reuters) - U.S. stocks slid on Wednesday, continuing a brutal month, as weak forecasts from chipmakers fanned concerns over the impact of tariffs and China's slowdown on corporate profit, even though Boeing hiked its outlook.
The benchmark S&P 500 is on a six-day losing streak and has fallen in 14 of the 18 trading days this month, pounded by worries ranging from rising borrowing costs and bond yields to Italy's budget and upcoming U.S. mid-term elections.
After disappointing forecasts from industrial giants Caterpillar and 3M on Tuesday, chipmakers Texas Instruments and STMicroelectronics warned of slowing demand on Wednesday.
"There is a lot of market angst at present. One thing that has been critical in sustaining a bull market has been earnings ... and they're not as robust as the first half of the year," said Bryan Reilly, a managing director at CIBC Private Wealth Management.
"Tariffs are certainly getting a lot of attention and companies are bracing for further tariff hikes, and should that persist there is only one way for corporate optimism to go given that we are at an all-time high."
Texas Instruments dropped 3.9 percent, helping pull the Philadelphia Semiconductor index down 3.10 percent. Advanced Micro Devices, which reports after the bell, fell 5.3 percent and Intel, reporting Thursday, shed 2.1 percent.
The beaten-down S&P technology sector retreated another 1.47 percent. Microsoft, which also reports after the bell, declined 2 percent.
Results from S&P 500 companies so far have been strong, pushing up third-quarter profit growth estimates to 22.4 percent from 21.6 percent in the last 10 days, but dour forecasts have pulled down fourth-quarter growth estimates to 19.5 percent from 20 percent, according to Refinitiv data.
A notable exception was Boeing, the largest U.S. exporter to China, which rose 3.8 percent after raising its full-year profit outlook. That helped the Dow Jones Industrial Average open higher, before the mood soured.
At 12:59 p.m. ET, the Dow was down 98.57 points, or 0.39 percent, at 25,092.86, the S&P 500 was down 24.56 points, or 0.90 percent, at 2,716.13 and the Nasdaq Composite was down 111.82 points, or 1.50 percent, at 7,325.72.
AT&T tumbled 5.9 percent after U.S. wireless carrier's quarterly profit rose less than expected, held back by its declining satellite TV business.
That also weighed on other media companies and dragged the communications services sector down 2.07 percent, the most among the 11 major sectors.
Only the defensive utilities, real estate and consumer staples posted gains.
Ford, due to report after the closing bell, fell 2.7 percent.
Declining issues outnumbered advancers for a 1.74-to-1 ratio on the NYSE and a 2.40-to-1 ratio on the Nasdaq.
The S&P recorded 10 new 52-week highs and 39 new lows. The Nasdaq recorded 14 new highs and 278 new lows. (Reporting by Amy Caren Daniel in Bengaluru; Editing by Arun Koyyur)