Mayor Vincent C. Gray will keep a $417 million budget surplus in the District government’s savings account, building the city’s reserves to $1.5 billion — the highest level since 2005 and the second highest total since the city gained limited independence from Congress. In total, the District revenues came in 2 percent higher than anticipated. Despite the windfall, mayoral officials said they do not anticipate proposing any new spending until Chief Financial Officer Natwar M. Gandhi issues new revenue projections in February for the current and upcoming fiscal years. The surplus will remain untouched, Gray administration officials said: ”None of it is up for grabs,” one senior official said. Should new revenues be revised upward, the Gray administration anticipates making ”major critical investments” in affordable housing, public safety and the raises for the District workforce.