Arbella Insurance Group, an auto insurer, is planning to reduce premium costs by up to 28% next year under a proposed rate filing made to the Massachusetts division of insurance.

According to Arbella’s filing, the average rate cut for the company’s approximately 350,000 drivers will be about 7.7%. However, about a third of Arbella’s drivers could see rate cuts of 20% or more and more than half could see cuts greater than 10%, according to the figures filed with the state. An estimated 8% of Arbella customers are eligible to receive a cut of 28%.

John Donohue, chairman and CEO of Arbella, said: In all, we think 75% of our drivers will see rate decreases in the first year of managed competition, and a third of them will see really significant decreases. This is only the beginning as we make further discounts and enhancements available to our best customers. We have vowed to be among the most competitive domestic companies in the auto insurance market. And we will be.