Party hats stayed out on Wall Street last week. Following news of an eleventh-hour deal in Washington to keep the nation from going over the so-called fiscal cliff, the Dow jumped 308 points, its biggest gain in more than a year. Investors are betting that absent Washington screwing things up, the ingredients for a stronger economy—and fatter corporate profits—this year are falling into place. Among other encouraging signs, an index of the confidence level among American consumers—whose spending drives much of the economy—ended the year 12.9 points higher than where it had begun. It was the biggest such swing in the Bloomberg Consumer Comfort Index in 24 years. In a grittier measure of consumer confidence, a group of major retailers reported that their sales in the crucial holiday month of December bumped up an average 4.5% over December 2011, despite all the talk of another meltdown in D.C. Nordstrom, the Seattle-based chain that will open its first Manhattan location in five years, saw sales spike by 8.6% at stores open at least a year. Even a closely watched manufacturing index, which had slumped to a three-year low in November, managed to bounce back a bit in December. The Institute for Supply Management’s index hit 50.7, up 1.2 points in the month—a reading that signals a return to growth in the sector.