GIFD Captain Todd Morgan said the Equitable Bank sign was engulfed in flames when crews arrived at the Locust Street location at 5:55 a.m.
Morgan said $5,000 worth of damage was done before the fire was put out.
He said it was started by some kind of electrical problem in the sign.
Seventeen firefighters were on scene, along with a ladder truck, three engines and an ambulance.
Morgan said the fire could have been a lot worse if the flames would have ignited the stucco bank building just six inches away.