(Adds portfolio manager comment, updates prices to close)
* TSX ends down 2.85 points, or 0.02 percent, at 15,200.76
* Index gained 0.6 percent in holiday-shortened week
* Six of the TSX's 10 main groups fell
TORONTO, May 22 (Reuters) - Canada's main stock index barely retreated on Friday, with cooling energy and financial stocks weighing, after the index posted gains in four of the previous five sessions.
Investors took a cautious approach ahead of a U.S. trading holiday on Monday, though U.S. dollar strength hurt some energy stocks as crude prices slipped. Energy stocks were five of the 10 biggest negative weights on the Toronto Stock Exchange's S&P/TSX composite index.
Banks were also among the biggest losers ahead of their quarterly earnings due through the next week.
U.S. Federal Reserve Chair Janet Yellen provided further evidence that the central bank is poised to raise rates this year as the U.S. economy bounces back from an early-year slump.
The TSX index ended off 2.85 points, or 0.02 percent, at 15,200.76. It gained 0.6 percent in a four-session week.
"It seem like markets are pricing in a reasonable chance of a rate increase in the U.S. at some point this year and that's helping boost the U.S. dollar and conversely putting pressure on commodity prices," said Youssef Zohny, portfolio manager at StennerZohny Investment Partners+ of Richardson GMP.
U.S. and Brent crude prices were both down around 1.5 percent.
Pipeline operator Enbridge Inc was the most influential loser, falling 1.1 percent to C$62.00. Bank of Nova Scotia followed with a 0.6 percent loss to C$64.61.
Despite the roughly flat performance overall, declining issues outnumbered advancing ones by 144 to 95.
"This is a market that's rallied quite strongly over the past little while. Essentially the market's just a little tired right now," said John Stephenson, president and CEO of Stephenson & Company Capital Management.
"I honestly don't see any problem going higher, but right now it's a long weekend in the U.S. coming up, and I think people are a little fatigued truthfully ... You also have commodity prices weaker, which is a big driver."
Many global markets will be closed on Monday, with Memorial Day holiday in the United States and a public holiday in much of Europe.
Countering some of the losses was a 0.8 percent gain among tech companies and a 0.5 percent gain in healthcare.