(Refiles to correct spelling of Ackman in paragraph 13)
* Canada-U.S. NAFTA renegotiation approaches deadline
* All 3 major U.S. indexes poised to post weekly gains
* Nasdaq poised for biggest one-month gain since January
* VIX rises in low volume, pre-holiday session
* Ford drops on ending plans to sell Chinese-made vehicle in U.S.
* Indexes down: Dow 0.38 pct, S&P 0.30 pct; Nasdaq 0.04
By Stephen Culp
NEW YORK, Aug 31 (Reuters) - The S&P 500 and the Dow were down and the Nasdaq edged higher in light trading on Friday as investors reacted to the possibility that a new Canada-U.S. trade agreement could miss a deadline heading into the Labor Day weekend.
Capping a low-volume, late-summer week marked by tariff-related volatility, all three major U.S. indexes looked set to show net gains for the period. The indexes are also on track to be up for the month of August, with the Nasdaq posting its largest monthly gain since January.
Trade talks between Canada and the United States had yet to clear some remaining hurdles as negotiators struggled to meet a Friday deadline.
The CBOE Volatility index, a gauge of investor anxiety, moved higher on this and other trade developments, including a report that U.S. President Donald Trump is prepared to impose tariffs on an additional $200 billion of Chinese imports as soon as next week.
"Normally when (trading) volume goes down if you have some major headlines the effect on the markets gets magnified," said Don Steinbrugge, managing partner at Agecroft Partners in Richmond, Virginia. "It can significantly increase volatility."
Amazon.com's shares continued to inch upward, rising 0.3 percent as investors watch the company close in on its $1 trillion market share milestone.
Apple Inc was up 1.1 percent, on track for posting a new high for five straight sessions.
The Dow Jones Industrial Average fell 73.76 points, or 0.28 percent, to 25,913.16, the S&P 500 lost 6 points, or 0.21 percent, to 2,895.13 and the Nasdaq Composite added 7.20 points, or 0.09 percent, to 8,095.56.
Of the 11 major sectors in the S&P 500, eight were trading lower.
Coca-Cola Co agreed to buy the coffee chain Costa from Britain's Whitbread PLC for $5.1 billion. . Its shares dipped 1.1 percent.
Tesla Inc was on its way to posting its fifth consecutive decline following news that fund manager BlackRock voted in favor of replacing Elon Musk with an independent chairman.
Shares of gun maker American Outdoor Brands were the top percentage gainer on the Nasdaq. The stock soared 38.1 percent after its upbeat earnings report. Peer Sturm Ruger & Co shares were up 7.4 percent.
Chipotle Mexican Grill shares extended their loss, dipping 1.9 percent after William Ackman's Pershing Square cut its stake in the burrito chain.
Ford Motor Co dropped 2.9 percent after scrapping a plan to sell a Chinese-made small vehicle in the United States due to tariff concerns.
General Motors was down 1.2 percent.
Declining issues outnumbered advancing ones on the NYSE by a 1.22-to-1 ratio; on Nasdaq, a 1.26-to-1 ratio favored advancers.
The S&P 500 posted 27 new 52-week highs and 3 new lows; the Nasdaq Composite recorded 99 new highs and 24 new lows.
Reporting by Stephen Culp; Editing by Dan Grebler