The Fitch Credit Rating Agency in New York has dropped Montgomery County’s bond rating from AAA to AA+, citing a continuing decline in the county’s fund balance following several years of operating deficits. Fitch Analyst Eric Freidman says property tax rates are well below the rates in other suburban counties, but past decisions to hold county tax rates constant as state aid dropped contributed to the lower rating, which can lead to higher borrowing costs because the county might have to offer higher interest rates to attract investors.