In the context that I believe you are using the term "supplemental" that would be a short term disability policy offered as a voluntary (employee paid) benefit at your place of employment. there are a variety of insurance carriers who offer such products with AFLAC, Colonial Life and Allstate being just a few examples. These products are generally offered at the workplace and are paid for via payroll deduction with your employer remitting the monthly premium to the insurance carrier. Unlike many supplemental/worksite/voluntary employee benefits such as critical illness plans, cancer and accident policies, I would not recommend that you have a disability insurance policy's premium taken out of your paycheck on a pre-tax basis as this could have tax implications in the event you ended up receiving benefits from the policy.
In addition to the definition provided by Mr. McKelvy supplemental short term disability can be used as a secondary policy for other disability plans. Supplemental is defined as: "added to furnish what is lacking or missing".
For example, people working in states with mandated coverage may want to increase the level of monthly benefit, or extend the length of payment duration. Or if employers offer a long term disability policy it may come with a lengthy elimination period. Many workers may go bankrupt before benefit payments begin on a policy with a 180 day waiting period.
For example, people working in states with mandated coverage may want to increase the level of monthly benefit, or extend the length of payment duration. Or if employers offer a long term disability policy it may come with a lengthy elimination period. Many workers may go bankrupt before benefit payments begin on a policy with a 180 day waiting period.