Side A-only coverage refers to a directors and officers (D&O) liability policy that provides only "direct" coverage of the directors and officers but does not cover the corporation's legal obligation to indemnify the directors and officers (known as Side B or corporate reimbursement coverage).
Side A-only forms are written either on an excess or umbrella basis over a primary D&O policy. When written on an excess basis, they provide additional limits if a claim exhausts the coverage available under the primary form. When written on an umbrella basis, Side A-only policies afford broader coverage than the underlying, primary D&O policy as well as additional limits.