A monthly index that seeks to measure business confidence in Massachusetts fell 4.3 points in November as local employers fretted about the so-called fiscal cliff, a combination of steep tax increases and deep budget cuts that will go into effect early next year unless President Obama and Congress can devise an alternative plan.

The index is maintained by the Associated Industries of Massachusetts, or AIM, a group that represents Bay State employers. The index uses a 100-point scale. A reading above 50 indicates that the state’s employer community is predominantly optimistic, and a reading below 50 points suggests a negative outlook.