Chapter 8
Supplemental Insurance/Complementary Crossover/Medigap

8.1 Overview

This section provides an explanation of supplemental insurance, complementary crossover, and Medigap policies. Additionally, we have listed the complementary crossover plans in our contract areas to which a beneficiary can subscribe. Please be sure to refer to this section whenever a beneficiary indicates that they have a Complementary Crossover plan.

8.2 Supplemental Insurance

Employer supplemental coverage is a supplemental health insurance plan offered by the beneficiary's or beneficiary's spouse's former employer to supplement Medicare coverage.

Because of the stringent requirements of Medigap coverage, some employer supplemental coverage plans participate as complementary crossover plans, while others do not. In order to be reimbursed for coinsurance by an employer supplemental plan that does not participate as a complementary crossover, the beneficiary or the provider must submit charges on their own to the employer supplemental plan.

8.3 Complementary Crossover

Listed on the following pages are 54 supplemental insurance companies that participate in the automatic transfer of Medicare claim information with HGSAdministrators. This process is known as complementary crossover. Complementary crossover is a method of transferring Medicare claim information to insurance companies that offer policies which supplement Medicare coverage. As contrasted to a Medigap claims transfer where Medicare claim information of only participating providers is transferred, complementary crossover provides for the automatic transfer of Medicare claim data to insurers from both nonparticipating providers as well as from participating providers.

To participate in complementary crossover, each of the 54 supplemental insurers have entered into a written agreement with HGSAdministrators for the automatic transfer of Medicare claim information. Each insurance company is required to provide us with an eligibility file of their Medicare eligible beneficiaries who have supplemental insurance policies with them. The eligibility file is the only method of ensuring that a claim will be transferred to the supplemental insurer. If the beneficiary does not appear on the eligibility file, no claim information will be transferred to the supplemental insurer.

When a match occurs between Medicare claim information and the insurer's eligibility file, the Medicare claim information will be forwarded to that insurer. While some of the supplemental insurers listed have nationwide coverage, our transfer of claim information is limited to the beneficiaries listed on the eligibility file.  Please note, additions or deletions of beneficiaries to the eligibility file are controlled by the supplemental insurer. Inquiries concerning the beneficiary's status on the eligibility file should be directed to the supplemental insurer.

a. Complementary Crossover Plans

The following companies have signed contracts for supplemental crossover with HGSAdministrators.  Coverage is extended to all Medicare eligible beneficiaries based on eligibility files we receive from the Coordination of Benefits (COB) Insurer. Therefore, it is not necessary to report any information about the COB Insurer on the Medicare claim.


Aetna Life and Casualty 
American Family Life Assurance Company (AFLAC)
American Postal Workers Union (APWU) 
AARP/United Health Care
Benefit Planners Inc.
BC/BS of Alabama 
BC/BS of Delaware (BC/BS DEL) 
Blue Cross and Blue Shield of Minnesota
BC/BS of New Jersey (BC/BS NJ) 
BC/BS of Oklahoma .
BC/BS of Virginia - Trigon 
BC/BS of United Wisconsin  .
CareFirst BC/BS (MD)
CareFirst BC/BS (Metro DC)
Caterpillar Inc.
Central States Health and Life.
Claims Administration  Corp
Continental Life Insurance Company
Delaware Medicaid 
Empire Blue Cross and Blue Shield 
Equicor (CIGNA)
Fairfax County Teachers
Government Employees Hospital Association 
Group Health Insurance 
Harvest Life/Federal Home
Health Data Management Corp (HDMC)
Intercounty Hospital Plan 
Kirke-Van Orsdel Inc. 
Maryland Medicaid 
Metrahealth/United Health Care 
Monumental Life Insurance Company 
Mutual of Omaha 
National Association of Letter Carriers 
New Jersey Medicaid 
Olympic Health Management Systems, Inc.
PA Employee Benefits Trust 
Pennsylvania Blue Shield 
Pennsylvania Medicaid
Peoples Benefit Life Insurance Co.
Physicians Mutual Insurance Co. 
Pioneer Life Insurance Company 
Prudential Insurance Company 
Special Agents Mutual Benefits Assoc. 
Stirling and Stirling 
United American Insurance 
United Commercial Travelers 
United Teachers Association (Fortis, Inc.)
Union Bankers Insurance
Union Fidelity
WorldNet Services Corporation

8.4 Medigap

The term Medigap refers to Medicare supplemental insurance. It is private health insurance designed specifically to supplement Medicare benefits by filling in some of the gaps in Medicare coverage. Examples of some of the gaps in Medicare coverage are:

The definition of a Medigap policy under Federal law does not include all insurance products that may help Medicare beneficiaries cover out-of-pocket costs. For example, a health plan offered by a company for current or former employees or by a labor organization for current or former members does not qualify as a Medigap insurance policy.

Medigap coverage varies depending upon the terms of the Medigap policy. Some Medigap policies provide coverage for Medicare's deductibles and most pay the hospital and medical coinsurance amounts. Federal law requires that, as a minimum, a Medigap policy sold as of July 30, 1992, must provide basic "core" benefits available in Plan A. There are 9 other standardized Medigap benefit Plans B through J contain the core "group of benefits" plus different combinations of additional benefits. The core benefits include:

For participating providers, when the Medigap information is provided, Medicare will automatically advise the Medigap insurer of Medicare's approved amount and payment for the billed services. The Medigap insurer can then determine their liability and make payment to the participating provider. This "one-step" billing eliminates the need for you to submit a separate bill to the beneficiary or their Medigap insurer after receiving  Medicare's payment. For additional information for placement of Medigap information on a HCFA 1500 (12-90) claim form, please refer to Chapter 9. Reporting requirements for  Medigap information are as follows.


Electronic Claims

Paper Claims


Version 30.51
3B.000 and 30.51.

Version 30.32

NSF Versions
001.04,002.00 and 

1500 Claim Form

SBR Segment 
03 Data Element 
SBR Segment 
03 Data Element

Record DAO 
02 Sequence
Positions 69-88

Block 9a

Insurer ID
NMI Segment 
09 Data Element
2-480 BA 
NMI Segment 
09 Data Element
Record DA0
02 Sequence
Positions 27-31

Block 9d

Release of Information Indicator 2-130
09 Data
11 Data
Record EA0
Field 13
Record 45

a. (MCE) Medicare Claims Express Reporting
The Medigap/Insurer ID code is reported on the insurance table, please follow the below steps to select a Medigap insurer that already exists on the insurance file, or to add a new Medigap insurance company.

a.1 Selecting a Medigap Insurer; already exists on insurance table.

1. From main menu screen, click on file maintenance icon.
2. Click on insurance folder.
3. Click on the ellipse (three dots) beside the INS code field. This will give you a list of insurances.
4. To select an insurance, highlight your selection by clicking on your choice, then click the “OK” check box.
5. Click on save before closing screen.

a.2 To Add a New Medigap Insurance Company; not on our insurance table.

1. From main screen, click in file maintenance icon.
2. Click on insurance folder.
3. Click on add box (this will clear your screen and enable you to add the new insurance).
4. Complete entire screen fields from the top to bottom.

Note: The information for the Insurer ID code block can be found in chapter 8, under supplemental insurance/complementary crossover/medigap instructions.

5. Click on the down arrow and highlight Medigap for the insurance type block.
6. Click on save before closing screen .

8.5 Medigap/Insurer ID Listing

HGSAdministrators developed a listing to ease the reporting of Medigap address information. The listing is an alphabetical list of insurers that offer Medigap policies. Each Medigap insurer has been assigned a new Medigap/Insurer ID code (previously called
co-codes). Participating physicians or suppliers are required to utilize the listing in the following section to obtain the
Medigap/Insurer ID code.

Note: HGSAdministrators cannot crossover claim information to the appropriate supplemental insurer without the appropriate insurer ID code. Claims that contain the name and address of the medigap company but not the new insurer ID code, will not be sent to the secondary insurer. The use of the new insurer ID code, along with the Medigap group policy number and insured's or authorized person's's signature, will allow the claim to be sent to the secondary insurer.

a. Medigap/Insurer ID Listing