When it comes to keeping New Year's resolutions, the bulls on Wall Street have outdone themselves.
The S&P 500 was supposed to finish the year at 1,490, according to CNNMoney's survey of more than 30 investment strategists in December. After a big move in January, it's already firmly above 1,500.
The 5% gain in January was the best start to a year for S&P 500 since 1997. If it continued at that near-impossible rate, the index would log a full-year return of 78.5%, said Mark Luschini, chief investment strategist at Janney Montgomery Scott.
"Needless to say, this performance begs the question as to whether this pace is sustainable," said Luschini.
Investors rushed into stocks last month after officials in Washington reached a deal on the fiscal cliff.
The rally, which pushed stocks near all-time highs, coincided with record inflows into stock-based mutual funds, as individual investors regained some appetite for risk after shunning stocks for years.
But the bullish tone has already started to fade.
"We're certainly off to a great start," said Jack Ablin, chief investment officer at BMO Private Bank. "But we may have gotten a little ahead of ourselves."
Most don't expect a textbook stock market correction, when major gauges drop 10% from their most recent highs. But a pause or pullback of some sort is increasingly likely.
"We've had a dramatic rally, and it needs to be corrected. But that doesn't mean the market has to go down," said Dan Greenhaus, market strategist at BTIG. "I'd be surprised to see a big move one way or the other."