* Dollar hits six-week low, gold up for third day
* Qualcomm plummets on Apple's $1 bln lawsuit
* Auto parts retailers down on likely Amazon competition
* Indexes down: Dow 0.31 pct, S&P 0.46 pct, Nasdaq 0.31 pct (Adds details, comments, updates prices)
By Yashaswini Swamynathan
Jan 23 (Reuters) - The S&P 500 was on track for its worst day this year as President Donald Trump's protectionist stance on trade sent investors scurrying for safe-haven assets on Monday.
In his latest executive order, Trump signed to formally withdraw the United States from the 12-nation Trans-Pacific partnership trade deal.
Earlier in the day, Trump met with a dozen prominent American manufacturers at the White House and said he would slash regulations and cut corporate taxes to boost the economy.
"The markets are less enthusiastic about protectionism than they are about pro-growth policies such as cutting taxes and decreasing regulation," said Art Hogan, chief market strategist at Wunderlich Equity Capital Markets.
The Trump rally, which led Wall Street to repeated highs since the election, has stalled in recent weeks as investors fretted about the potential impact of his isolationist stance on world trade and the lack of clarity on his policies.
Trump has also vowed to renegotiate the North American Free Trade Agreement (NAFTA) with leaders of Canada and Mexico.
At 12:34 p.m. ET (1734 GMT), the Dow was down 61.03 points, or 0.31 percent, at 19,766.22, the S&P 500 was down 10.15 points, or 0.46 percent, at 2,261.16 and the Nasdaq Composite was down 17.38 points, or 0.31 percent, at 5,537.96.
The dollar hit a six-week low on Monday, while prices of safe-haven gold soared to their highest since Nov. 22.
U.S. crude prices fell 0.86 percent on signs of strong drilling activity. The S&P energy index hit its lowest level since Nov. 30.
Eight other S&P sectors were also lower. Defensive sectors telecom services and real-estate were the outliers.
Qualcomm dropped 12.6 percent to $54.94 after Apple filed a $1 billion lawsuit against the chip supplier on Friday. Qualcomm was the biggest drag on the S&P and the Nasdaq, while Apple's stock was flat.
Halliburton fell 3.9 percent after the world's No. 2 oilfield services provider reported a bigger loss in the latest quarter.
Shares of auto parts retailers Autozone, Advance Auto Parts, O'Reilly fell between 2.5 percent and 4.8 percent after the NY Post said Amazon.com may start selling auto parts. The online retailer's stock was up 0.1 percent.
Declining issues outnumbered advancers on the NYSE by 1,580 to 1,301. On the Nasdaq, 1,843 issues fell and 899 advanced.
The S&P 500 index showed 13 new 52-week highs and six new lows, while the Nasdaq recorded 65 new highs and 36 new lows. (Reporting by Yashaswini Swamynathan in Bengaluru; Editing by Anil D'Silva)