Montgomery County finance officials are now expecting a $520 million budget shortfall, $70 million bigger than earlier projections.
Finance director Jennifer Barrett told the county council Tuesday that weak housing and stock markets have led to declining income and real estate taxes.
The county already faced a projected $450 million gap, about 11 percent of the $4 billion budget.
County Executive Isiah Leggett is expected to release his spending plan for fiscal 2010 in about three weeks. Leggett and the council have pledged not to raise taxes, warning of deep cuts in government services to balance the budget.