Put yesterday's Dow chart up to a mirror and what you'll see is almost exactly what happened today.  Just as yesterday was a consistent and quite dramatic slope downwards, today it was just as consistently and almost as dramatically sloping upwards, upwards to the tune of 227 points.  What happened?  Quite simply, oil finally had a really good day, good enough to send the entire S&P energy index up almost 5 percent.  This led many investors today to believe that maybe oil had finally hit a bottom and thus began a buying spree.  The S&P too gained a lot of ground rising again above 1900 and taking it out of correction territory (for the whole one day it was there), though just barely so at a 9.8 rather than 10 percent loss since the May 2015 high.  More important, today's market sentiment is that what we have seen so far this year is likely not the start of a new bear market at all and that Q4 earnings may be more positive than feared, and that will all lead to a stronger market yet.  So today there was a furious amount of buying to the tune of an amazing 10 billion shares.  Even Warren Buffett got in on the action investing heavily in oil.

Markets | Thu Jan 14, 2016 6:18pm EST

Energy leads Wall Street rebound; S&P has best day since December

NEW YORK | BY CAROLINE VALETKEVITCH     reuters

DJ:  16,379.05  +227.64     NAS: 4,615.01  +88.94        S&P:  1,921.84  +31.56

A rally in battered energy shares led U.S. stocks to rebound on Thursday, while financials rose after upbeat results from JPMorgan Chase & Co.  The S&P 500 had its biggest daily percentage gain since December and ended back above 1,900.

Though the market finished off its highs for the day, analysts said some investors see a bottom in energy shares, which were among the most heavily sold shares in the market's rout that began at the start of the year.  The S&P energy sector .SPNY shot up 4.5 percent, its best percentage gain since late August.

Shares of Exxon Mobil XOM.N surged 4.6 percent to $79.12 while Chevron CVX.N jumped 5.1 percent to $85.47, among the biggest boosts to the Dow and S&P 500. U.S. and Brent oil prices ended more than 2 percent higher.

Also rebounding were biotechs, with the Nasdaq Biotech Index .NBI ending up 4.0 percent.

"You have had people trying to pick a bottom both in the energy commodity itself and energy shares a few times in this long slide down and again today," said Rick Meckler, president of LibertyView Capital Management in Jersey City, New Jersey.

He said exchange-traded funds may have bought energy stocks, forcing short-sellers to cover positions.

The Dow Jones industrial average .DJI was up 227.64 points, or 1.41 percent, to 16,379.05, the S&P 500 .SPX had gained 31.56 points, or 1.67 percent, to 1,921.84 and the Nasdaq Composite .IXIC had added 88.94 points, or 1.97 percent, to 4,615.00.

The S&P 500 remains down 9.8 percent from its May 21, 2015, record closing high, and analysts said plenty of caution remains, thanks to lingering concerns about demand for oil and a slowdown in the global economy.

Daniel Morgan, senior portfolio manager at Synovus Trust Company in Atlanta, said he does not see stocks headed for a bear market, adding that upbeat earnings reports from tech and other companies could put the market on stronger footing.

JPMorgan JPM.N rose 1.5 percent to $58.20 on better-than-expected results. Citigroup C.N, Wells Fargo WFC.N, Morgan Stanley MS.N and Bank of America BAC.N also rose.

Chipotle CMG.N was up 6.1 percent at $454.30 after the company expressed confidence in preventing future food poisoning outbreaks at its chains.

Advancing issues outnumbered declining ones on the NYSE by 2,079 to 1,005, for a 2.07-to-1 ratio on the upside; on the Nasdaq, 1,961 issues rose and 899 fell for a 2.18-to-1 ratio favoring advancers.

The S&P 500 posted 1 new 52-week high and 115 new lows; the Nasdaq recorded 6 new highs and 439 new lows.

About 10.0 billion shares changed hands on U.S. exchanges, compared with the 7.5 billion daily average for the past 20 trading days, according to Thomson Reuters data.