* Stocks resume declines after snapping 5-day losing streak
* Healthcare, tech biggest sector losers
* Energy shares climb along with oil prices
* Indexes down: Dow 0.28 pct, S&P 0.3 pct, Nasdaq 0.77 pct (Updates to late afternoon)
By Lewis Krauskopf
June 17 (Reuters) - Wall Street dropped on Friday as Apple shares weighed on major indexes and investors girded for Britain's vote next week on its European Union membership.
The three indexes were each on track to post weekly declines of at least 1 percent, as the possibility that Britain will vote to leave on June 23 has been rattling global markets. On Thursday, Wall Street had snapped a five-session streak of declines.
"I think it's investors taking positions off the table here going into the last weekend prior to the 'Brexit' vote," Chuck Carlson, chief executive officer at Horizon Investment Services in Hammond, Indiana, said of Friday's declines.
The Dow Jones industrial average was down 49 points, or 0.28 percent, at 17,684.1 and the S&P 500 lost 6.23 points, or 0.3 percent, at 2,071.76.
The tech-heavy Nasdaq Composite was down 37.46 points, or 0.77 percent, at 4,807.46.
Apple shares fell 1.8 percent. Apple said its iPhone 6 and 6 Plus were still available for sale in China after Beijing's intellectual property regulators barred sales saying the designs had infringed a Chinese company's patent.
"There seems to be this perpetual stream of kind of quasi-negative news surrounding some of the really big market cap stocks, like Apple particularly, and anytime you have got Apple misbehaving that tends to put a damper on the averages," Carlson said.
Fears over Brexit undercut the S&P 500's momentum after the benchmark index came within about 12 points of its record closing high last week. U.S. stock markets could see heavy trading and increased volatility as investors position for next week's referendum.
"Risk appetite has declined because of the Brexit vote," said Jeremy Zirin, head of investment strategy at UBS Wealth Management Americas in New York.
Six of the 10 S&P sectors were lower in afternoon trade. Energy shares were the best-performing group, gaining 0.8 percent, as oil prices rose for the first time in a week.
Recovering oil prices have helped the U.S. stock market rebound some 14 percent since mid-February. The S&P is now up more than 1 percent for the year.
On Friday, the healthcare sector was the biggest laggard, falling 1 percent.
Tech shares dropped 0.8 percent. The sector's declines were limited by Oracle, which rose 3 percent to $39.79 after better-than-expected quarterly revenue. The stock gave the biggest boost to the S&P.
Advancing issues outnumbered declining ones on the NYSE by 1,811 to 1,155, for a 1.57-to-1 ratio on the upside; on the Nasdaq, 1,536 issues fell and 1,214 advanced for a 1.27-to-1 ratio favoring decliners.
The S&P 500 posted 9 new 52-week highs and 2 new lows; the Nasdaq recorded 27 new highs and 32 new lows. (Additional reporting by Yashaswini Swamynathan in Bengaluru; Editing by Don Sebastian and Nick Zieminski)