By Ryan Vlastelica
NEW YORK (Reuters) - U.S. stock investors head into the Thanksgiving holiday thankful for the market's recent strength, which puts major indexes on track for another year of double-digit gains, though the swiftness of the advance has raised eyebrows.
The S&P 500 (.SPX) is up 13.3 percent from an intraday low hit on Oct. 15, and the gains since then have been broad. Since that bottom, all but 23 S&P 500 components are higher.
The magnitude of the rally has some concerned. Several notable fund managers at this week's Reuters Investment Outlook Summit said they don't expect stocks to do much in 2015.
Citigroup on Thursday wrote that the market was "on the edge of euphoria ... causing us to be more cautious," while Goldman Sachs on Wednesday released its 2015 year-end target of 2,100 - just 1.8 percent above current levels.
The recent stretch of solid earnings and economic figures, however, leaves managers puzzled over what could hurt the market going forward.
"It's tough for me to wrap my head around the next big move being lower," said David Lebovitz, global market strategist at J.P. Morgan Funds in New York. "Some people aren't comfortable with current levels, but fundamentals remain strong."
The market's recent gains prompted a notable commentary from the Federal Reserve Bank of San Francisco on Nov. 13 that pointed out certain valuation metrics look stretched. It also noted that the ratio of NYSE margin debt to GDP in September stood at an elevated level that, in the past, was "followed by major downturns in stock prices."
Jim McDonald, chief investment strategist at Chicago-based Northern Trust Asset Management, wasn't buying it. He said the level of margin debt is "more or less consistent with the trend line over the past 20-plus years," though a pullback was possible.
"The primary issue facing the market is that we've gotten a year's return out of the S&P in the past month," he said. "Investors are more than willing to take risk off the table after such a big run."
Volatility may pick up next week as many take off for Thanksgiving. Markets are closed on Thursday and will close early on Friday.
However, December has historically been the best month of the year for the S&P, according to the Stock Trader's Almanac, averaging a rise of 1.7 percent.
Energy names have jumped sharply since the October low, which could make them liable to profit taking, especially going into the Organization of the Petroleum Exporting Countries' Nov. 27 meeting, when members will consider whether to cut output to shore up prices.
Chesapeake Energy (CHK.N), Newfield Exploration (NFX.N), CONSOL Energy (CNX.N) and Marathon Petroleum Corp (MPC.N) have all gained more than 20 percent since the market's October low.
(Editing by Nick Zieminski)