* Facebook gains after announcing changes to privacy settings
* Tesla slips after U.S. opens probe on fatal crash
* Stocks set for their worst month since Jan. 2016
* Dow up 0.38 pct, S&P up 0.22 pct, Nasdaq off 0.27 pct (Updates to open)
By Sruthi Shankar
March 28 (Reuters) - The Nasdaq Composite index fell on Wednesday, dragged down by losses in Amazon and Apple, while gains in healthcare stocks propped up the Dow and the S&P 500.
Amazon fell more than 5 percent after reports that President Donald Trump is looking to target the company by changing its tax treatment.
Apple dropped 1.6 percent after Goldman Sachs analyst cut sales estimate for iPhone for March and June quarters, citing weak demand.
However, Facebook's shares rose more than 2 percent after the company said it was giving users more control over their privacy by making data management easier and redesigning the settings menu.
The social network has lost more than $100 billion in market value since March 16, when it first acknowledged that user data had been improperly harvested by a consultancy firm.
"We had Facebook making some announcements. That's obviously taking some pressure off the stock at the moment," said Andre Bakhos, managing director of New Vines Capital LLC in Bernardsville, New Jersey.
"It's enough to get some short covering, but as far as pouring in, most investors will wait until the dust settles."
Broader markets have suffered this month on a back-and-forth between the United States and China on tariffs and fears of rising interest rates. The main indexes are on track for their worst month since January 2016.
Comments from top officials in the United States and China had given a sense that both the countries would negotiate over President Donald Trump's move to impose tariffs on Chinese goods.
China is expected to soon announce a list of retaliatory tariffs on US exports, its state-run Global Times reported on Wednesday.
At 9:55 a.m. ET, the Dow Jones Industrial Average was up 90.99 points, or 0.38 percent, at 23,948.7 and the S&P 500 was up 5.87 points, or 0.22 percent, at 2,618.49.
The Nasdaq Composite was down 18.60 points, or 0.27 percent, at 6,990.21.
The S&P healthcare index was up nearly 1 percent on gains in Allergan, Celgene and Incyte.
Tesla dropped about 4.4 percent after the U.S. government said it would investigate a fatal crash and vehicle fire of a Model X in California.
Lululemon Athletica surged 8.8 percent after the Canadian athletic apparel maker posted a surprisingly strong fourth-quarter profit and forecast further growth in the first quarter.
Advancing issues outnumbered decliners on the NYSE for a 1.41-to-1 ratio and for a 1.06-to-1 ratio on the Nasdaq. (Reporting by Sruthi Shankar in Bengaluru; Editing by Anil D'Silva)