Apple and other tech companies led the market up for the second day Thursday. The gains came a day after Apple took its worst fall in four years. Investors’ biggest concern remains the automatic tax increases and federal spending cuts scheduled to start Jan. 1. Most investors believe President Obama and congressional Republicans will strike a budget deal before the year is out. But until they reach an agreement, the stock market will likely be hostage to news out of Washington. The government will release its monthly jobs report Friday. Private economists expect the unemployment rate to remain unchanged at 7.9 percent.