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.