a08505a6_Medical_billing__November_2010__Notes
[BlockNo.] 9a [Block Name] Other Insured’s Policy and Group Number [Block Code] A [Notes] 
This block identifies a secondary insurance other than MA, and the primary insurance listed in 11a- d. Enter the policy number and the group number of any secondary insurance that is available. Only use Blocks 9a-d, if you have completed Blocks 11a-d, and a secondary policy is available. (For example, the patient may have both Blue Cross and Aetna benefits available.)
CMS 1500 claim and UB 04 form- Medical billing: November 2010
Notes