The Nasdaq is having its best day in nearly three weeks. As usual, Apple (NASDAQ: AAPL) is the catalyst behind the tech-heavy index’s big move. Apple shares had climbed 2.5% as of 2:45 p.m. eastern time. As it often does, the Nasdaq was riding the coattails of the world’s largest company, gaining 1.3%. Black Friday was the last time the Nasdaq gained this much ground in one day. There are other factors contributing to today’s positive returns. There’s a growing perception that fiscal cliff negotiations have become more serious, feeding investor optimism that a deal may soon get done. That positivity was enough to push the other indices up a few ticks as well. The S&P 500 and Dow Jones Industrial Average each gained half a percent. Other big movers on Tuesday included: Delta Air Lines (NYSE: DAL): +5.5% on the strength of its deal to buy a 49% stake in Virgin Atlantic . Urban Outfitters (NASDAQ: URBN): +5% after the clothing retailer’s improved outlook for its fourth-quarter sales. Research In Motion (NASDAQ: RIMM): +5.5% after the company unveiled a new feature for its new BlackBerry 10 phone, scheduled for release on January 30.