* Pfizer drops as quarterly revenue misses estimates
* Fed begins two-day policy meeting
* Oil slips on worries about Iran sanction
* Indexes down: Dow 0.59 pct, S&P 0.20 pct, Nasdaq 0.02 pct (Updates to open)
By Sruthi Shankar
May 1 (Reuters) - U.S. stocks slipped on Tuesday as the latest batch of earnings from companies such as Pfizer and Tapestry disappointed investors already concerned about rising costs and protectionist policies.
A drop in oil prices, due to uncertainties around the Iran nuclear deal, weighed on energy stocks. The S&P energy index was down 0.9 percent.
U.S. equity index futures got a bump overnight after President Donald Trump postponed the imposition of steel and aluminum tariffs on Canada, the European Union and Mexico until June 1, and reached agreements for permanent exemptions for Argentina, Australia and Brazil.
The decision comes ahead of Treasury Secretary Steven Mnuchin's highly anticipated trip to China later this week to discuss trade issues.
Shares of AK Steel and U.S. Steel were down more than 3 percent.
At 10:00 a.m. ET the Dow Jones Industrial Average was down 143.28 points, or 0.59 percent, at 24,019.87, the S&P 500 was down 5.25 points, or 0.20 percent, at 2,642.80 and the Nasdaq Composite was down 1.54 points, or 0.02 percent, at 7,064.73.]
"You had the tariff news, but that may have already been baked in," said Scott Brown, chief economist at Raymond James in St. Petersburg, Florida.
"It causes the same amount of uncertainty, you had worse-than-expected revenue from Pfizer, and there might be some caution ahead of Apple results."
Pfizer fell 2.3 percent after the largest U.S. drugmaker's quarterly revenue missed estimates. Merck shares also dipped 0.6 percent despite profit beating estimates and the company lifting earnings forecast for the year.
Tapestry, formerly Coach, tumbled 12 percent after it reported a drop in quarterly margins and a steeper-than-expected decline in same-store sales in its Kate Spade business.
Apple, the world's biggest publicly traded company, comes out with results after market closes on Tuesday.
The U.S. Federal Reserve begins its two-day monetary policy meeting on Tuesday. Although no change in policy rates is expected, investors will watch for clues on whether three more rate hikes are due for the rest of 2018.
Trading volumes could remain light as most financial centers across Europe and Asia were closed on account of May Day.
Declining issues outnumbered advancers for a 1.97-to-1 ratio on the NYSE and for a 1.92-to-1 ratio on the Nasdaq.
The S&P index recorded one new 52-week high and 16 new lows, while the Nasdaq recorded 22 new highs and 44 new lows. (Reporting by Sruthi Shankar in Bengaluru; Editing by Shounak Dasgupta)