NEW YORK — The “fiscal cliff’’ compromise, even with all its chaos, controversy, and unresolved questions, was enough to ignite the stock market on Wednesday, the first trading day of the new year.
The Dow Jones industrial average careened more than 300 points higher, its biggest gain since December 2011. It’s now just 5 percent below its record high close, reached in October 2007. The Russell 2000, an index that tracks smaller companies, shot up to 873.42, the highest close in its history.
The reverie multiplied across the globe, with stock indexes throughout Europe and Asia leaping higher. A leading British index, the FTSE 100, closed above 6,000 for the first time since July 2011, at 6,027.37.
In the United States, the rally was extraordinarily broad. For every stock that fell on the New York Stock Exchange, roughly 10 rose. All 30 stocks that make up the Dow rose, as did 94 percent of the stocks in the Standard & Poor’s 500 index.
US government bond prices dipped sharply as investors pulled money out of safe-harbor investments. And the VIX, the “fear index” that measures investors’ expectations of future market volatility, plunged more than 18 percent to 14.68, the lowest close since October.
The very last week of each year and the first two days of the new year usually average out to a gain for US stocks. But the size of this year’s gains made it stand out.
The Dow has risen on the first day of the trading year for each of the past four years, from 2009 to 2012. The average gain was 171 points — sizable, but still much smaller than Wednesday’s leap of 308.41 points.
In the midst of the euphoria, many investors remained cautious. The deal that politicians hammered out merely postpones the country’s budget reckoning, they said, rather than averting it.
‘‘Washington negotiations remind me of the Beach Boys song, ‘We’ll have fun, fun, fun ‘til her daddy takes the T-Bird away,’ ” Jack Ablin, chief investment officer of BMO Private Bank in Chicago, wrote in a note to clients.
“Nothing got solved,” added T. Doug Dale, chief investment officer for Security Ballew Wealth Management in Jackson, Miss.
According to these and other market watchers, investors were celebrating Wednesday not because they love the budget deal that was cobbled together, but because they were grateful there was any deal at all.
‘‘Most people think that no deal would have been worse than a bad deal,’’ said Mark Lehmann, the president of JMP Securities in San Francisco.
The bill that passed Tuesday night ended the stalemate for now, but it leaves many questions unanswered.
The deal doesn’t include any significant deficit-cutting agreement, meaning the country still doesn’t have a long-term plan or even an agreement in principle on how to rein in spending. Big cuts to defense and domestic programs, which were slated to kick in with the new year, weren’t worked out but instead were just delayed for two months. And the United States is still bumping up against its borrowing limit, or ‘‘debt ceiling.’’
‘‘There’s definitely another drama coming down the road,’’ Lehmann said. “That’s the March cliff.’’
The political bickering that’s almost certain to persist could have another unwelcome effect: influencing ratings agencies to cut the US government’s credit score.
That happened before, when Standard & Poor’s cut its rating on US government debt in August 2011, and the stock market plunged.