<PAGE>
                                                                   EXHIBIT 10.18


     Contract with Eligible Medicare Advantage (MA) Organization Pursuant to
     Sections 1851 through 1859 of the Social Security Act for the Operation
                of a Medicare Advantage Coordinated Care Plan(s)

                                CONTRACT (H4513)

                                     Between

    Centers for Medicare & Medicaid Services (hereinafter referred to as CMS)

                                       and

                            TEXAS HEALTHSPRING I, LLC
                (hereinafter referred to as the MA Organization)

CMS and the MA Organization, an entity which has been determined to be an
eligible Medicare Advantage Organization by the Administrator of the Centers for
Medicare & Medicaid Services under 42 CFR 422.503, agree to the following for
the purposes of sections 1851 through 1859 of the Social Security Act
(hereinafter referred to as the Act):

(NOTE: Citations indicated in brackets are placed in the text of this contract
to note the regulatory authority for certain contract provisions. All references
to Part 422 are to 42 CFR Part 422.)

YOU MUST CHECK OFF AND INITIAL EACH REQUIRED ADDENDUM TYPE TO REFLECT THE
COVERAGE OFFERED UNDER THE H (OR R) NUMBER ASSOCIATED WITH THIS CONTRACT

<TABLE>
<CAPTION>
ADDENDUM TYPE                                            INITIALS
-------------                                            --------
<S>                                                      <C>
[X]  PART D ADDENDUM                                     ________

[ ]  EMPLOYER-ONLY MA-PD ADDENDUM (800 SERIES)           ________

[X]  EMPLOYER-ONLY MA ONLY ADDENDUM (800 SERIES)         ________

[ ]  VARIANCES/WAIVERS (PROVIDED DIRECTLY TO
     DEMONSTRATION ORGANIZATIONS BY CMS)                 ________

[ ]  REGIONAL PREFERRED PROVIDER ORGANIZATION ADDENDUM
     (PROVIDED DIRECTLY TO RPPOS BY CMS)                 ________
</TABLE>

<PAGE>

                                    Article I

                                Term of Contract

The term of this contract shall be from the date of signature by CMS' authorized
representative through December 31, 2006, after which this contract may be
renewed for successive one-year periods in accordance with 42 CFR 422.505(c) and
as discussed in Paragraph A in Article VII below. [422.505]

This contract governs the respective rights and obligations of the parties as of
the effective date set forth above, and supersedes any prior agreements between
the MA Organization and CMS as of such date. MA organizations offering Part D
also must execute an Addendum to the Medicare Managed Care Contract Pursuant to
Sections 1860D-1 through 1860D-42 of the Social Security Act for the Operation
of a Voluntary Medicare Prescription Drug Plan (hereafter the "Part D
Addendum"). For MA Organizations offering MA-PD plans, the Part D Addendum
governs the rights and obligations of the parties relating to the provision of
Part D benefits, in accordance with its terms, as of its effective date.

                                   Article II

                              Coordinated Care Plan

A. The Medicare Advantage Organization agrees to operate one or more coordinated
care plans as defined in 42 CFR 422.4(a)(1)(iii)), including at least one MA-PD
plan as required under 42 CFR 422.4(c), as described in its final Plan Benefit
Package (PBP) bid submission (benefit and price bid) proposal as approved by CMS
and as attested to in the Medicare Advantage Attestation of Benefit Plan and
Price, and in compliance with the requirements of this contract and applicable
Federal statutes, regulations, and policies.

B. Except as provided in paragraph (C) of this Article, this contract is deemed
to incorporate any changes that are required by statute to be implemented during
the term of the contract and any regulations or policies implementing or
interpreting such statutory provisions.

C. CMS will not implement, other than at the beginning of a calendar year,
requirements under 42 CFR Part 422 that impose a new significant cost or burden
on MA organizations or plans, unless a different effective date is required by
statute. [422.521]

                                   Article III

          Functions To Be Performed By Medicare Advantage Organization

A. PROVISION OF BENEFITS

1. The MA Organization agrees to provide enrollees in each of its MA plans the
basic benefits as required under Section 422.101 and, to the extent applicable,
supplemental benefits under Section 422.102 and as established in the MA
Organization's final benefit and price bid proposal as approved by CMS and
listed in the MA Organization Plan Attestation of Benefit Plan and Price, which
is attached to this contract. The MA Organization agrees to provide access to
such benefits as required under subpart C in a manner consistent with
professionally recognized standards of health care and according to the access
standards stated in Section 422.112.

2 The MA Organization agrees to provide post-hospital extended care services,
should an MA

<PAGE>

enrollee elect such coverage, through a skilled nursing home facility according
to the requirements of section 1852(1) of the Act and Section 422.133. A skilled
nursing home facility is a facility in which an MA enrollee resided at the time
of admission to the hospital, a facility that provides services through a
continuing care retirement community, a facility in which the spouse of the
enrollee is residing at the time of the enrollee's discharge from the hospital,
or hospital, or wherever the enrollee resides immediately before admission for
extended care services.

[ ]  [422.133; 422.504(A)(3)]

[ ]  B. ENROLLMENT REQUIREMENTS

1 The MA Organization agrees to accept new enrollments, make enrollments
effective, process voluntary disenrollments, and limit involuntary
disenrollments, as provided in subpart B of part 422.

2 The MA Organization shall comply with the provisions of Section 422.110
concerning prohibitions against discrimination in beneficiary enrollment, other
than in enrolling eligible beneficiaries in a CMA-approved special needs plan
that exclusively enrolls special needs individuals as consistent with Sections
422.2, 422.4(a)(l)(iv) and 422.52.

[422.504(A)(2)]

C. BENEFICIARY PROTECTIONS

1 The MA Organization agrees to comply with all requirements in subpart M of
part 422, governing coverage determinations, grievances, and appeals.
[422.504(A)(7)]

2 The MA Organization agrees to comply with the confidentiality and enrollee
record accuracy requirements in Section 422.118.

3 Beneficiary Financial Protections. The MA Organization agrees to comply with
the following requirements:

[ ]  (a) Each MA Organization must adopt and maintain arrangements satisfactory
to CMS to protect its enrollees from incurring liability for payment of any fees
that are the legal obligation of the MA Organization. To meet this requirement
the MA Organization must--

[ ]  (i) Ensure that all contractual or other written arrangements with
providers prohibit the Organization's providers from holding any beneficiary
enrollee liable for payment of any fees that are the legal obligation of the MA
Organization; and

[ ]  (ii) Indemnify the beneficiary enrollee for payment of any fees that are
the legal obligation of the MA Organization for services furnished by providers
that do not contract, or that have not otherwise entered into an agreement with
the MA Organization, to provide services to the organization's beneficiary
enrollees. [422.504(G)(1)]

[ ]  (b) The MA Organization must provide for continuation of enrollee health
care benefits-

[ ]  (i) For all enrollees, for the duration of the contract period for which
CMS payments have been made; and

[ ]  (ii) For enrollees who are hospitalized on the date its contract with CMS
terminates, or, in the event of the MA Organization's insolvency, through the
date of discharge. [422.504(G)(2)]

[ ]  (c) In meeting the requirements of this section (C), other than the
provider contract requirements specified in paragraph (C)(3)(a) of this Article,
the MA Organization may use--

[ ]  (i) Contractual arrangements;

[ ]  (ii) Insurance acceptable to CMS;

[ ]  (iii) Financial reserves acceptable to CMS; or

<PAGE>

[ ]  (iv) Any other arrangement acceptable to CMS. [422.504(G)(3)]

[ ]  D. PROVIDER PROTECTIONS

1 The MA Organization agrees to comply with all applicable provider requirements
in 42 CFR Part 422 Subpart E, including provider certification requirements,
anti-discrimination requirements, provider participation and consultation
requirements, the prohibition on interference with provider advice, limits on
provider indemnification, rules governing payments to providers, and limits on
physician incentive plans. [422.504(A)(6)]

2 Prompt Payment.

[ ]  (a) The MA Organization must pay 95 percent of "clean claims" within 30
days of receipt if they are claims for covered services that are not furnished
under a written agreement between the organization and the provider.

[ ]  (i) The MA Organization must pay interest on clean claims that are not paid
within 30 days in accordance with sections 1816(c)(2) and 1842(c)(2) of the Act.

[ ]  (ii) All other claims from non-contracted providers must be paid or denied
within 60 calendar days from the date of the request. [422.520(A)]

[ ]  (b) Contracts or other written agreements between the MA Organization and
its providers must contain a prompt payment provision, the terms of which are
developed and agreed to by both the MA Organization and the relevant provider.
[422.520(B)]

     (c) If CMS determines, after giving notice and opportunity for hearing,
that the MA Organization has failed to make payments in accordance with
subparagraph (2)(a) of this section, CMS may provide--

     (i) For direct payment of the sums owed to providers; and

[ ]  (ii) For appropriate reduction in the amounts that would otherwise be paid
to the MA Organization, to reflect the amounts of the direct payments and the
cost of making those payments. [422.520(C)]

[ ]  E. QUALITY IMPROVEMENT PROGRAM

1 The MA Organization agrees to operate, for each plan that it offers, an
ongoing quality improvement program as stated in accordance with Section 1852(e)
of the Social Security Act and 42 CFR 422.152.

2 Chronic Care Improvement Program

[ ]  (a) Each MA organization (other than MA private-fee-for-service plans) must
have a chronic care improvement program and must establish criteria for
participation in the program. The CCIP must have a method for identifying
enrollees with multiple or sufficiently severe chronic conditions who meet the
criteria for participation in the program and a mechanism for monitoring
enrollees' participation in the program.

[ ]  (b) Plans have flexibility to choose the design of their program; however,
in addition to meeting the requirements specified above, the CCIP selected must
be relevant to the plan's MA population. MA organizations are required to submit
annual reports on their CCIP program to CMS.

1 Performance Measurement and Reporting: The MA Organization shall measure
performance under its MA plans using standard measures required by CMS, and
report (at the organization level) its performance to CMS. The standard measures
required by CMS during the term of this contract will be uniform data collection
and reporting instruments, to include the Health Plan and Employer Data

<PAGE>

Information Set (HEDIS), Consumer Assessment of Health Plan Satisfaction (CAHPS)
survey, and Health Outcomes Survey (HOS). These measures will address clinical
areas, including effectiveness of care, enrollee perception of care and use of
services; and non-clinical areas including access to and availability of
services, appeals and grievances, and organizational characteristics.
[422.152(B)(1), (E)]

2 Utilization Review:

[ ]  (a) An MA Organization for an MA coordinated care plan must use written
protocols for utilization review and policies and procedures must reflect
current standards of medical practice in processing requests for initial or
continued authorization of services and have in effect mechanisms to detect both
underutilization and over utilization of services. [422.152(B)]

[ ]  (b) For MA regional preferred provider organizations (RPPOs) and MA local
preferred provider organizations (PPOs) that are offered by an organization that
is not licensed or organized under State law as an HMOs, if the MA Organization
uses written protocols for utilization review, those policies and procedures
must reflect current standards of medical practice in processing requests for
initial or continued authorization of services and include mechanisms to
evaluate utilization of services and to inform enrollees and providers of
services of the results of the evaluation. [422.152(E)].

5. Information Systems:

     (a) The MA Organization must:

[ ]  (i) Maintain a health information system that collects, analyzes and
integrates the data necessary to implement its quality improvement program;

[ ]  (ii) Ensure that the information entered into the system (particularly that
received from providers) is reliable and complete;

     (iii) Make all collected information available to CMS. [422.152(F)(1)]

6. External Review The MA Organization will comply with any requests by Quality
Improvement Organizations to review the MA Organization's medical records in
connection with appeals of discharges from hospitals, skilled nursing
facilities, and home health agencies.

F. COMPLIANCE PLAN The MA Organization agrees to implement a compliance plan in
accordance with the requirements of Section 422.503(b)(4)(vi).
[422.503(B)(4)(VI)]

G. COMPLIANCE DEEMED ON THE BASIS OF ACCREDITATION CMS may deem the MA
Organization to have met the quality improvement requirements of Section 1852(e)
of the Act and Section 422.152, the confidentiality and accuracy of enrollee
records requirements of Section 1852(h) of the Act and Section 422.118, the
anti-discrimination requirements of Section 1852(b) of the Act and Section
422.110, the access to services requirements of Section 1852(d) of the Act and
Section 422.112, and the advance directives requirements of Section 1852(i) of
the Act and Section 422.128, the provider participation requirements of Section
1852(j) of the Act and 42 CFR Part 422, Subpart F, and the applicable
requirements described in Section 423.165, if the MA Organization is fully
accredited (and periodically reaccredited) by a private, national accreditation
organization approved by CMS and the accreditation organization used the
standards approved by CMS for the purposes of assessing the MA Organization's
compliance with Medicare requirements. The provisions of Section 422.156 shall
govern the MA Organization's use of deemed status to meet MA program
requirements.

H. PROGRAM INTEGRITY

1 The MA Organization agrees to provide notice based on best knowledge,
information, and belief

<PAGE>

to CMS of any integrity items related to payments from governmental entities,
both federal and state, for healthcare or prescription drug services. These
items include any investigations, legal actions or matters subject to
arbitration brought involving the MA Organization (or MA Organization's firm if
applicable) and its subcontractors (excluding contracted network providers),
including any key management or executive staff, or any major shareholders (5%
or more), by a government agency (state or federal) on matters relating to
payments from governmental entities, both federal and state, for healthcare
and/or prescription drug services. In providing the notice, the sponsor shall
keep the government informed of when the integrity item is initiated and when it
is closed. Notice should be provided of the details concerning any resolution
and monetary payments as well as any settlement agreements or corporate
integrity agreements.

2 The MA Organization agrees to provide notice based on best knowledge,
information, and belief to CMS in the event the MA Organization or any of its
subcontractors is criminally convicted or has a civil judgment entered against
it for fraudulent activities or is sanctioned under any Federal program
involving the provision of health care or prescription drug services.

I. MARKETING

1 The MA Organization may not distribute any marketing materials, as defined in
42 CFR 422.80(b) and in the Marketing Materials Guidelines for Medicare
Advantage-Prescription Drug Plans and Prescription Drug Plans (Medicare
Marketing Guidelines), unless they have been filed with and not disapproved by
CMS in accordance with Section 422.80. The file and use process set out at
Section 422.80(a)(2) must be used, unless the MA organization notifies CMS that
it will not use this process.

2 CMS and the MA Organization shall agree upon language setting forth the
benefits, exclusions and other language of the Plan. The MA Organization bears
full responsibility for the accuracy of its marketing materials. CMS, in its
sole discretion, may order the MA Organization to print and distribute the
agreed upon marketing materials, in a format approved by CMS. The MA
Organization must disclose the information to each enrollee electing a plan as
outlined in 42 CFR 422.111.

3 The MA Organization agrees that any advertising material, including that
labeled promotional material, marketing materials, or supplemental literature,
shall be truthful and not misleading. All marketing materials must include the
Contract number. All membership identification cards must include the Contract
number on the front of the card.

4 The MA Organization must comply with the Medicare Marketing Guidelines, as
well as all applicable statutes and regulations, including and without
limitation Section 1851(h) of the Act

and 42 CFR Sections 422.80, 422.111 and 423.50. Failure to comply may result in
sanctions as provided in 42 CFR Part 422 Subpart O.

                                   Article IV

                         CMS Payment to MA Organization

A. The MA Organization agrees to develop its annual benefit and price bid
proposal and submit to CMS all required information on premiums, benefits, and
cost sharing, as required under 42 CFR Part 422 Subpart F. [422.504(A)(10)]

B. Methodology. CMS agrees to pay the MA Organization under this contract in
accordance with the provisions of section 1853 of the Act and 42 CFR Part 422
Subpart G. [422.504(A)(9)]

C. Attestation of payment data (Attachments A, B, and C). As a condition for
receiving a monthly

<PAGE>

payment under paragraph B of this article, and 42 CFR Part 422 Subpart G, the MA
Organization agrees that its chief executive officer (CEO), chief financial
officer (CFO), or an individual delegated with the authority to sign on behalf
of one of these officers, and who reports directly to such officer, must request
payment under the contract on the forms attached hereto as Attachment A
(enrollment attestation) and Attachment B (risk adjustment data) which attest to
(based on best knowledge, information and belief, as of the date specified on
the attestation form) the accuracy, completeness, and truthfulness of the data
identified on these attachments. The Medicare Advantage Plan Attestation of
Benefit Plan and Price must be signed and attached to the executed version of
this contract.

1  Attachment A requires that the CEO, CFO, or an individual delegated with the
authority to sign on behalf of one of these officers, and who reports directly
to such officer, must attest based on best knowledge, information, and belief
that each enrollee for whom the MA Organization is requesting payment is validly
enrolled, or was validly enrolled during the period for which payment is
requested, in an MA plan offered by the MA Organization. The MA Organization
shall submit completed enrollment attestation forms to CMS, or its contractor,
on a monthly basis. (NOTE: The forms included as attachments to this contract
are for reference only. CMS will provide instructions for the completion and
submission of the forms in separate documents. MA Organizations should not take
any action on the forms until appropriate CMS instructions become available.)

2  Attachment B requires that the CEO, CFO, or an individual delegated with the
authority to sign on behalf of one of these officers, and who reports directly
to such officer, must attest to (based on best knowledge, information and
belief, as of the date specified on the attestation form) that the risk
adjustment data it submits to CMS under Section 422.310 are accurate, complete,
and truthful. The MA Organization shall make annual attestations to this effect
for risk adjustment data on Attachment B and according to a schedule to be
published by CMS. If such risk adjustment data are generated by a related
entity, contractor, or subcontractor of an MA Organization, such entity,
contractor, or subcontractor must similarly attest to {based on best knowledge,
information, and belief as of the date specified on the attestation form) the
accuracy, completeness, and truthfulness of the data. [422.504(1)]

3  The Medicare Advantage Plan Attestation of Benefit Plan and Price (which is
attached hereto requires that the CEO, CFO, or an individual delegated with the
authority to sign on behalf of one of these officers, and who reports directly
to such officer, must attest (based on best knowledge, information and belief,
as of the date specified on the attestation form) that the information and
documentation comprising the bid submission proposal is accurate, complete, and
truthful and fully conforms to the Bid Form and Plan Benefit Package
requirements; and that the benefits described in the CMS-approved proposal bid
submission agree with the benefit package the MA Organization will offer during
the period covered by the proposal bid submission. This document is being sent
separately to the MA Organization and must be signed and attached to the
executed version of this contract, and is incorporated herein by reference.
[422.502(I))

                                    Article V

               MA Organization Relationship with Related Entities,
                         Contractors, and Subcontractors

A. Notwithstanding any relationship(s) that the MA Organization may have with
related entities, contractors, or subcontractors, the MA Organization maintains
full responsibility for adhering to and otherwise fully complying with all terms
and conditions of its contract with CMS.
[422.504(I)(1)]

<PAGE>

B. The MA Organization agrees to require all related entities, contractors, or
subcontractors to agree that--

     (1) HHS, the Comptroller General, or their designees have the right to
inspect, evaluate, and audit any pertinent contracts, books, documents, papers,
and records of the related entity(s), contractor(s), or subcontractor(s)
involving transactions related to this contract; and

     (2) HHS, the Comptroller General, or their designees have the right to
inspect, evaluate, and audit any pertinent information for any particular
contract period for 10 years from the final date of the contract period or from
the date of completion of any audit, whichever is later. [422.504(I)(2)]

C. The MA Organization agrees that all contracts or written arrangements into
which the MA Organization enters with providers, related entities, contractors,
or subcontractors (first tier and downstream entities) shall contain the
following elements:

     (1) Enrollee protection provisions that provide--

     (a) Consistent with Article III(C), arrangements that prohibit providers
from holding an enrollee liable for payment of any fees that are the legal
obligation of the MA Organization; and

     (b) Consistent with Article III(C), provision for the continuation of
benefits.

[ ]  (2) Accountability provisions that indicate that the MA Organization may
only delegate activities or functions to a provider, related entity, contractor,
or subcontractor in a manner consistent with requirements set forth at paragraph
D of this article.

     (3) A provision requiring that any services or other activity performed by
a related entity, contractor or subcontractor in accordance with a contract or
written agreement between the related entity, contractor, or subcontractor and
the MA Organization will be consistent and comply with the MA Organization's
contractual obligations to CMS. [422.504(I)(3)]

D. If any of the MA Organization's activities or responsibilities under this
contract with CMS is delegated to other parties, the following requirements
apply to any related entity, contractor, subcontractor, or provider:

     (1) Written arrangements must specify delegated activities and reporting
responsibilities.

[ ]  (2) Written arrangements must either provide for revocation of the
delegation activities and reporting requirements or specify other remedies in
instances where CMS or the MA Organization determine that such parties have not
performed satisfactorily.

     (3) Written arrangements must specify that the performance of the parties
is monitored by the MA Organization on an ongoing basis.

     (4) Written arrangements must specify that either--

[ ]  (a) The credentials of medical professionals affiliated with the party or
parties will be either reviewed by the MA Organization; or

[ ]  (b) The credentialing process will be reviewed and approved by the MA
Organization and the MA Organization must audit the credentialing process on an
ongoing basis.

[ ]  (5) All contracts or written arrangements must specify that the related
entity, contractor, or subcontractor must comply with all applicable Medicare
laws, regulations, and CMS instructions.

[422.504(I)(4)]

E. If the MA Organization delegates selection of the providers, contractors, or
subcontractors to another organization, the MA Organization's written
arrangements with that organization must state that the MA Organization retains
the right to approve, suspend, or terminate any such arrangement.
[422.504(I)(5)]

<PAGE>

F. As of the date of this contract and throughout its term, the MA Organization

[ ]  (1) Agrees that any physician incentive plan it operates meets the
requirements of Section 422.208, and

[ ]  (2) Has assured that all physicians and physician groups that the MA
Organization's physician incentive plan places at substantial financial risk
have adequate stop-loss protection in accordance with Section 422.208(f).
[422.208]

                                   Article VI

                              Records Requirements

A. MAINTENANCE OF RECORDS

1. The MA Organization agrees to maintain for 10 years books, records,
documents, and other evidence of accounting procedures and practices that--

     (a) Are sufficient to do the following:

[ ]  (i) Accommodate periodic auditing of the financial records (including data
related to Medicare utilization, costs, and computation of the benefit and price
bid) of the MA Organization.

[ ]  (ii) Enable CMS to inspect or otherwise evaluate the quality,
appropriateness and timeliness of services performed under the contract, and the
facilities of the MA Organization.

     (iii) Enable CMS to audit and inspect any books and records of the MA
Organization that pertain to the ability of the organization to bear the risk of
potential financial losses, or to services performed or determinations of
amounts payable under the contract.

[ ]  (iv) Properly reflect all direct and indirect costs claimed to have been
incurred and used in the preparation of the benefit and price bid proposal.

[ ]  (v) Establish component rates of the benefit and price bid for determining
additional and supplementary benefits.

     (vi) Determine the rates utilized in setting premiums for State insurance
agency purposes and for other government and private purchasers; and

     (b) Include at least records of the following:

[ ]  (i) Ownership and operation of the MA Organization's financial, medical,
and other record keeping systems.

     (ii) Financial statements for the current contract period and six prior
periods.

     (iii) Federal income tax or informational returns for the current contract
period and six prior periods.

[ ]  (iv) Asset acquisition, lease, sale, or other action.

[ ]  (v) Agreements, contracts (including, but not limited to, with related or
unrelated prescription drug benefit managers) and subcontracts.

[ ]  (vi) Franchise, marketing, and management agreements.

     (vii) Schedules of charges for the MA Organization's fee-for-service
patients.

     (viii) Matters pertaining to costs of operations.

[ ]  (ix) Amounts of income received, by source and payment.

[ ]  (x) Cash flow statements.

[ ]  (xi) Any financial reports filed with other Federal programs or State
authorities.

     [422.504(D)]

<PAGE>

2. Access to facilities and records. The MA Organization agrees to the
following:

[ ]  (a) The Department of Health and Human Services (HHS), the Comptroller
General, or their designee may evaluate, through inspection or other means--

[ ]  (i) The quality, appropriateness, and timeliness of services furnished to
Medicare enrollees under the contract;

     (ii) The facilities of the MA Organization; and

     (iii) The enrollment and disenrollment records for the current contract
period and ten prior periods.

     (b) HHS, the Comptroller General, or their designees may audit, evaluate,
or inspect any books, contracts, medical records, documents, papers, patient
care documentation, and other records of the MA Organization, related entity,
contractor, subcontractor, or its transferee that pertain to any aspect of
services performed, reconciliation of benefit liabilities, and determination of
amounts payable under the contract, or as the Secretary may deem necessary to
enforce the contract.

     (c) The MA Organization agrees to make available, for the purposes
specified in section

[ ]  (A) of this article, its premises, physical facilities and equipment,
records relating to its Medicare enrollees, and any additional relevant
information that CMS may require, in a manner that meets CMS record maintenance
requirements.

[ ]  (d) HHS, the Comptroller General, or their designee's right to inspect,
evaluate, and audit extends through 10 years from the final date of the contract
period or completion of audit, whichever is later unless-

[ ]  (i) CMS determines there is a special need to retain a particular record or
group of records for a longer period and notifies the MA Organization at least
30 days before the normal disposition date;

[ ]  (ii) There has been a termination, dispute, or fraud or similar fault by
the MA Organization, in which case the retention may be extended to 10 years
from the date of any resulting final resolution of the termination, dispute, or
fraud or similar fault; or

[ ]  (iii) HHS, the Comptroller General, or their designee determines that there
is a reasonable possibility of fraud, in which case they may inspect, evaluate,
and audit the MA Organization at any time. [422.502(E)]

[ ]  B. REPORTING REQUIREMENTS

1 The MA Organization shall have an effective procedure to develop, compile,
evaluate, and report to CMS, to its enrollees, and to the general public, at the
times and in the manner that CMS requires, and while safeguarding the
confidentiality of the doctor-patient relationship, statistics and other
information as described in the remainder of this section (B). [422.516(A)]

2 The MA Organization agrees to submit to CMS certified financial information
that must include the following:

     (a) Such information as CMS may require demonstrating that the organization
has a fiscally sound operation, including:

     (i) The cost of its operations;

[ ]  (ii) A description, submitted to CMS annually and within 120 days of the
end of the fiscal year, of significant business transactions (as defined in
Section 422.500) between the MA Organization and a party in interest showing
that the costs of the transactions listed in paragraph (2)(a)(v) of this section
do not exceed the costs that would be incurred if these transactions were with
someone who is not a party in interest; or

<PAGE>

     (iii) If they do exceed, a justification that the higher costs are
consistent with prudent management and fiscal soundness requirements.

     (iv) A combined financial statement for the MA Organization and a party in
interest if either of the following conditions is met:

     (aa) Thirty-five percent or more of the costs of operation of the MA
Organization go to a party in interest.

     (bb) Thirty-five percent or more of the revenue of a party in interest is
from the MA Organization. [422.516(B)]

     (v) Requirements for combined financial statements.

     (aa) The combined financial statements required by paragraph (2)(a)(iv)
must display in separate columns the financial information for the MA
Organization and each of the parties in interest.

     (bb) Inter-entity transactions must be eliminated in the consolidated
column.

     (cc) The statements must have been examined by an independent auditor in
accordance with generally accepted accounting principles and must include
appropriate opinions and notes.

     (dd) Upon written request from the MA Organization showing good cause, CMS
may waive the requirement that the organization's combined financial statement
include the financial information required in paragraph (2)(a)(v) with respect
to a particular entity. [422.516(C)]

[ ]  (vi) A description of any loans or other special financial arrangements the
MA Organization makes with contractors, subcontractors, and related entities.

[ ]  (b) Such information as CMS may require pertaining to the disclosure of
ownership and control of the MA Organization. [422.502(F)(1)(II)]

     (c) Patterns of utilization of the MA Organization's services.

3. The MA Organization agrees to participate in surveys required by CMS and to
submit to CMS all information that is necessary for CMS to administer and
evaluate the program and to simultaneously establish and facilitate a process
for current and prospective beneficiaries to exercise choice in obtaining
Medicare services. This information includes, but is not limited to:

     (a) The benefits covered under the MA plan;

[ ]  (b) The MA monthly basic beneficiary premium and MA monthly supplemental
beneficiary premium, if any, for the plan.

[ ]  (c) The service area and continuation area, if any, of each plan and the
enrollment capacity of each plan;

[ ]  (d) Plan quality and performance indicators for the benefits under the plan
including -

[ ]  (i) Disenrollment rates for Medicare enrollees electing to receive benefits
through the plan for the previous 2 years;

[ ]  (ii) Information on Medicare enrollee satisfaction;

[ ]  (iii) The patterns of utilization of plan services;

[ ]  (iv) The availability, accessibility, and acceptability of the plan's
services;

[ ]  (v) Information on health outcomes and other performance measures required
by CMS;

[ ]  (vi) The recent record regarding compliance of the plan with requirements
of this part, as determined by CMS; and

     (vii) Other information determined by CMS to be necessary to assist
beneficiaries in making an informed choice among MA plans and traditional
Medicare;

     (e) Information about beneficiary appeals and their disposition;

[ ]  (f) Information regarding all formal actions, reviews, findings, or other
similar actions by States,

<PAGE>

other regulatory bodies, or any other certifying or accrediting organization;

[ ]  (g) Any other information deemed necessary by CMS for the administration or
evaluation of the Medicare program. [422.502(F)(2)]

1  The MA Organization agrees to provide to its enrollees and upon request, to
any individual eligible to elect an MA plan, all informational requirements
under Section 422.64 and, upon an enrollee's, request, the financial disclosure
information required under Section 422.516. [422.502(F)(3)]

2  Reporting and disclosure under ERISA.

[ ]  (a) For any employees' health benefits plan that includes an MA
Organization in its offerings, the MA Organization must furnish, upon request,
the information the plan needs to fulfill its reporting and disclosure
obligations (with respect to the MA Organization) under the Employee Retirement
Income Security Act of 1974 (ERISA).

[ ]  (b) The MA Organization must furnish the information to the employer or the
employer's designee, or to the plan administrator, as the term "administrator"
is defined in ERISA. [422.516(D)]

1 Electronic communication. The MA Organization must have the capacity to
communicate with CMS electronically. [422.504(B)]

2 Risk Adjustment data. The MA Organization agrees to comply with the
requirements in Section 422.310 for submitting risk adjustment data to CMS.
[422.504(A)(8)]

                                   Article VII

                           Renewal of the MA Contract

A. Renewal of contract: In accordance with Section 422.505, following the
initial contract period, this contract is renewable annually only if-

     (1) The MA Organization has not provided CMS with a notice of intention not
to renew; [422.506(A)]

[ ]  (2) CMS and the MA Organization reach agreement on the bid under 42 CFR
Part 422, Subpart F; and [422.505(D)]

[ ]  (3) CMS informs the MA Organization that it authorizes a renewal.

[ ]  B. Nonrenewal of contract

[ ]  (1) Nonrenewal by the Organization.

[ ]  (a) In accordance with Section 422.506, the MA Organization may elect not
to renew its contract with CMS as of the end of the term of the contract for any
reason, provided it meets the time frames for doing so set forth in
subparagraphs (b) and (c) of this paragraph.

[ ]  (b) If the MA Organization does not intend to renew its contract, it must
notify--

[ ]  (i) CMS, in writing, by the first Monday in June of the year in which the
contract would end, pursuant to Section 422.506

[ ]  (ii) Each Medicare enrollee, at least 90 days before the date on which the
nonrenewal is effective. This notice must include a written description of all
alternatives available for obtaining Medicare services within the service area
including alternative MA plans, Medigap options, and original Medicare and
prescription drug plans and must receive CMS approval prior to issuance.

     (iii) The general public, at least 90 days before the end of the current
calendar year, by

<PAGE>

publishing a CMS-approved notice in one or more newspapers of general
circulation in each community located in the MA Organization's service area.

[ ]  (c) CMS may accept a nonrenewal notice submitted after the applicable
annual non-renewal notice deadline if --

[ ]  (i) The MA Organization notifies its Medicare enrollees and the public in
accordance with subparagraph (1)(b)(ii) and (1)(b)(iii) of this section; and

[ ]  (ii) Acceptance is not inconsistent with the effective and efficient
administration of the Medicare program.

[ ]  (d) If the MA Organization does not renew a contract under subparagraph
(1), CMS will not enter into a contract with the Organization for 2 years from
the date of contract separation unless there are special circumstances that
warrant special consideration, as determined by CMS.

[422.506(A)]

     (2) CMS decision not to renew.

[ ]  (a) CMS may elect not to authorize renewal of a contract for any of the
following reasons:

[ ]  (i) The MA Organization's level of enrollment, growth in enrollment, or
insufficient number of contracted providers is determined by CMS to threaten the
viability of the organization under the MA program and or be an indicator of
beneficiary dissatisfaction with the MA plan(s) offered by the organization.

[ ]  (ii) For any of the reasons listed in Section 422.510(a) [Article VIII,
section (B)(1)(a) of this contract], which would also permit CMS to terminate
the contract.

     (iii) The MA Organization has committed any of the acts in Section
422.752(a) that would support the imposition of intermediate sanctions or civil
money penalties under 42 CFR Part 422 Subpart O.

[ ]  (iv) The MA Organization did not submit a benefit and price bid or the
benefit and price bid was not acceptable [422.505(D)]

[ ]  (b) Notice. CMS shall provide notice of its decision whether to authorize
renewal of the contract as follows:

[ ]  (i) To the MA Organization by May 1 of the contract year, except in the
event of (2)(a)(iv) above, for which notice will be sent by September 1.

[ ]  (ii) To the MA Organization's Medicare enrollees by mail at least 90 days
before the end of the current calendar year.

     (iii) To the general public at least 90 days before the end of the current
calendar year, by publishing a notice in one or more newspapers of general
circulation in each community or county located in the MA Organization's service
area.

     (c) Notice of appeal rights. CMS shall give the MA Organization written
notice of its right to reconsideration of the decision not to renew in
accordance with Section 422.644.
[422.506(B)]

                                  Article VIII

                   Modification or Termination of the Contract

A. Modification or Termination of Contract by Mutual Consent

1. This contract may be modified or terminated at any time by written mutual
consent.

[ ]  (a) If the contract is modified by written mutual consent, the MA
Organization must notify its Medicare enrollees of any changes that CMS
determines are appropriate for notification within time

<PAGE>

frames specified by CMS. [422.508(A)(2)]

[ ]  (b) If the contract is terminated by written mutual consent, except as
provided in section (A)(2) of this Article, the MA Organization must provide
notice to its Medicare enrollees and the general public as provided in section
B(2)(b)(ii) and B(2)(b)(iii) of this Article. [422.508(A)(1)]

2. If this contract is terminated by written mutual consent and replaced the day
following such termination by a new MA contract, the MA Organization is not
required to provide the notice specified in section B of this article.
[422.508(B)]

B. Termination of the Contract by CMS or the MA Organization

1. Termination by CMS.

     (a) CMS may terminate a contract for any of the following reasons:

[ ]  (i) The MA Organization has failed substantially to carry out the terms of
its contract with CMS.

[ ]  (ii) The MA Organization is carrying out its contract with CMS in a manner
that is inconsistent with the effective and efficient implementation of 42 CFR
Part 422.

     (iii) CMS determines that the MA Organization no longer meets the
requirements of 42 CFR Part 422 for being a contracting organization.

[ ]  (iv) There is credible evidence that the MA Organization committed or
participated in false, fraudulent or abusive activities affecting the Medicare
program, including submission of false or fraudulent data.

[ ]  (v) The MA Organization experiences financial difficulties so severe that
its ability to make necessary health services available is impaired to the point
of posing an imminent and serious risk to the health of its enrollees, or
otherwise fails to make services available to the extent that such a risk to
health exists.

[ ]  (vi) The MA Organization substantially fails to comply with the
requirements in 42 CFR Part 422 Subpart M relating to grievances and appeals.

     (vii) The MA Organization fails to provide CMS with valid risk adjustment
data as required under Section 422.310 and 423.329(b)(3).

     (viii) The MA Organization fails to implement an acceptable quality
improvement program as required under 42 CFR Part 422 Subpart D.

[ ]  (ix) The MA Organization substantially fails to comply with the prompt
payment requirements in Section 422.520.

[ ]  (x) The MA Organization substantially fails to comply with the service
access requirements in Section 422.112.

[ ]  (xi) The MA Organization fails to comply with the requirements of
Section 422.208 regarding physician incentive plans.

     (xii) The MA Organization substantially fails to comply with the marketing
requirements in 422.80.

[ ]  (b) Notice. If CMS decides to terminate a contract for reasons other than
the grounds specified in section (B)(1)(a) above, it will give notice of the
termination as follows:

[ ]  (i) CMS will notify the MA Organization in writing 90 days before the
intended date of the termination.

[ ]  (ii) The MA Organization will notify its Medicare enrollees of the
termination by mail at least

<PAGE>

30 days before the effective date of the termination.

     (iii) The MA Organization will notify the general public of the termination
at least 30 days before the effective date of the termination by publishing a
notice in one or more newspapers of general circulation in each community or
county located in the MA Organization's service area.

     (c) Immediate termination of contract by CMS.

[ ]  (i) For terminations based on violations prescribed in paragraph
(B)(1)(a)(v) of this article, CMS will notify the MA Organization in writing
that its contract has been terminated effective the date of the termination
decision by CMS. If termination is effective in the middle of a month, CMS has
the right to recover the prorated share of the capitation payments made to the
MA Organization covering the period of the month following the contract
termination.

[ ]  (ii) CMS will notify the MA Organization's Medicare enrollees in writing of
CMS' decision to terminate the MA Organization's contract. This notice will
occur no later than 30 days after CMS notifies the plan of its decision to
terminate this contract. CMS will simultaneously inform the Medicare enrollees
of alternative options for obtaining Medicare services, including alternative MA
Organizations in a similar geographic area and original Medicare.

     (iii) CMS will notify the general public of the termination no later than
30 days after notifying the MA Organization of CMS' decision to terminate this
contract. This notice will be published in one or more newspapers of general
circulation in each community or county located in the MA Organization's service
area.

     (d) Corrective action plan

[ ]  (i) General. Before terminating a contract for reasons other than the
grounds specified in section (B)(1)(a)(v) of this article, CMS will provide the
MA Organization with reasonable opportunity, not to exceed time frames specified
at 42 CFR Part 422 Subpart N, to develop and receive CMS approval of a
corrective action plan to correct the deficiencies that are the basis of the
proposed termination.

[ ]  (ii) Exception. If a contract is terminated under section (B)(l)(a)(v) of
this article, the MA Organization will not have the opportunity to submit a
corrective action plan.

[ ]  (e) Appeal rights. If CMS decides to terminate this contract, it will send
written notice to the MA Organization informing it of its termination appeal
rights in accordance with 42 CFR Part 422 Subpart N. [422.510]

2. Termination by the MA Organization

     (a) Cause for termination. The MA Organization may terminate this contract
if CMS fails to substantially carry out the terms of the contract.

     (b) Notice. The MA Organization must give advance notice as follows:

[ ]  (i) To CMS, at least 90 days before the intended date of termination. This
notice must specify the reasons why the MA Organization is requesting contract
termination.

[ ]  (ii) To its Medicare enrollees, at least 60 days before the termination
effective date. This notice must include a written description of alternatives
available for obtaining Medicare services within the service area, including
alternative MA and MA-PD plans, PDP plans, Medigap options, and original
Medicare and must receive CMS approval.

     (iii) To the general public at least 60 days before the termination
effective date by publishing a CMS-approved notice in one or more newspapers of
general circulation in each community or county located in the MA Organization's
geographic area.

[ ]  (c) Effective date of termination. The effective date of the termination
will be determined by

<PAGE>

CMS and will be at least 90 days after the date CMS receives the MA
Organization's notice of intent to terminate.

[ ]  (d) CMS' liability. CMS' liability for payment to the MA Organization ends
as of the first day of the month after the last month for which the contract is
in effect, but CMS shall make payments for amounts owed prior to termination but
not yet paid.

[ ]  (e) Effect of termination by the organization. CMS will not enter into an
agreement with the MA Organization for a period of two years from the date the
Organization has terminated this contract, unless there are circumstances that
warrant special consideration, as determined by CMS. [422.512]

                                   Article IX

                   Requirements of Other Laws and Regulations

A. The MA Organization agrees to comply with-

     (1) Federal laws and regulations designed to prevent or ameliorate fraud,
waste, and abuse, including, but not limited to, applicable provisions of
Federal criminal law, the False Claims Act (31 USC 3729 et seq.), and the
anti-kickback statute (section 1128B(b) of the Act): and

     (2) HIPAA administrative simplification rules at 45 CFR parts 160, 162, and
164. [422.504(H)]

B. The MA Organization maintains ultimate responsibility for adhering to and
otherwise fully complying with all terms and conditions of its contract with
CMS, notwithstanding any relationship(s) that the MA organization may have with
related entities, contractors, or subcontractors. [422.504(I)]

C. In the event that any provision of this contract conflicts with the
provisions of any statute or regulation applicable to an MA Organization, the
provisions of the statute or regulation shall have full force and effect.

                                    Article X

                                  Severability

The MA Organization agrees that, upon CMS' request, this contract will be
amended to exclude any MA plan or State-licensed entity specified by CMS, and a
separate contract for any such excluded plan or entity will be deemed to be in
place when such a request is made. [422.504(K)]

                                   Article XI

                                  Miscellaneous

A. Definitions. Terms not otherwise defined in this contract shall have the
meaning given to such terms in 42 CFR Part 422.

B. Alteration to Original Contract Terms. The MA Organization agrees that it has
not altered in any way the terms of this contract presented for signature by
CMS. The MA Organization agrees that any alterations to the original text the MA
Organization may make to this contract shall not be binding on the parties.

C. Approval to Begin Marketing and Enrollment. The MA Organization agrees that
it must complete

<PAGE>

CMS operational requirements prior to receiving CMS approval to begin Part C
marketing and enrollment activities. Such activities include, but are not
limited to, establishing and successfully testing connectivity with CMS systems
to process enrollment applications (or contracting with an entity qualified to
perform such functions on the MA Organization's Sponsor's behalf) and
successfully demonstrating capability to submit accurate and timely price
comparison data. To establish and successfully test connectivity, the MA
Organization must, 1) establish and test physical connectivity to the CMS data
center, 2) acquire user identifications and passwords, 3) receive, store, and
maintain data necessary to perform enrollments and send and receive transactions
to and from CMS, and 4) check and receive transaction status information.

D. Incorporation of Applicable Addenda. All addenda checked off and initialed on
the cover sheet of this contract by the MA Organization are hereby incorporated
by reference.

In witness whereof, the parties hereby execute this contract.

FOR THE PDP SPONSOR

JEFF ROTHENBERGER                       SR. VP & CORPORATE COO
Printed Name                            Title


/s/ Jeff Rothenberger                   9/7/05
-------------------------------------   Date
Signature

TEXAS HEALTHSPRING I, LLC
Organization

2900 NORTH LOOP WEST, SUITE 1300, HOUSTON, TX 77292
Address

FOR THE CENTERS FOR MEDICARE & MEDICAID SERVICES


/s/ Patricia P. Smith                   10/12/05
-------------------------------------   Date
Patricia P. Smith
Director Medicare Advantage Group
Center for Beneficiary Choices

<PAGE>

            EMPLOYER/UNION-ONLY GROUP PART C ADDENDUM TO CONTRACT WITH
          APPROVED ENTITY PURSUANT TO SECTIONS 1851 THROUGH 1859 OF THE
          SOCIAL SECURITY ACT FOR THE OPERATION OF A MEDICARE ADVANTAGE
                                      PLAN

The Centers for Medicare & Medicaid Services (hereinafter referred to as "CMS")
and TEXAS HEALTHSPRING I, LLC, a Medicare Advantage Organization (hereinafter
referred to as the "MA Organization") agree to amend the contract H4513
governing the MA Organization's operation of a Medicare Advantage plan described
in section 1851(a)(2)(A) or section 1851(a)(2)(C) of the Social Security Act
(hereinafter referred to as "the Act"), including all attachments, addenda, and
amendments thereto, to include the provisions contained in this Addendum
(collectively hereinafter referred to as the "contract"), under which the MA
Organization shall offer Employer/Union-Only Group MA-Only Plans (hereinafter
referred to as "employer/union-only group health plans") in accordance with the
waivers granted by CMS under section 1857(i) of the Act. The terms of this
Addendum shall only apply to MA-only health plans offered exclusively to
employers/unions.

This Addendum is made pursuant to Subpart K of 42 CFR Part 422.

                                    ARTICLE I
            EMPLOYER/UNION-ONLY GROUP MEDICARE ADVANTAGE HEALTH PLAN

A.   MA Organization agrees to operate one or more employer/union-only group
     health plans in accordance with the terms of this Addendum, the Medicare
     Advantage contract (except for requirements contained therein that are
     expressly waived or modified by this Addendum), all provisions of Federal
     statutes, regulations, and policies applicable to MA organizations or MA
     plans (except to the extent any such provisions are expressly waived or
     modified by this Addendum), and any employer/union-only group waiver
     guidance.

B.   This Addendum is deemed to incorporate any changes that are required by
     statute to be implemented during the term of the contract, and any
     regulations and policies implementing or interpreting such statutory
     provisions.

C.   In the event of any conflict between the employer/union-only group waiver
     guidance issued prior to the execution of the contract and this Addendum,
     the provisions of this Addendum shall control. In the event of any conflict
     between the employer/union-only group waiver guidance issued after the
     execution of the contract and this Addendum, the provisions of the
     employer/union-only group guidance shall control.

D.   This Addendum is in no way intended to supersede or modify 42 CFR Part 422
     or sections 1851 through 1859 of the Act, except as specifically provided
     in applicable employer/union-only group waiver guidance and/or in this
     Addendum. Failure to reference a statutory or regulatory requirement in
     this Addendum does not affect the applicability of such requirement to the
     MA Organization and CMS.

E.   The provisions of this Addendum apply to all employer/union-only group
     health plans offered by MA Organization. In the event of any conflict
     between the provisions of this Addendum and any other provision of the
     contract, the terms of this Addendum shall control.

<PAGE>

                                   ARTICLE II
        FUNCTIONS TO BE PERFORMED BY THE MEDICARE ADVANTAGE ORGANIZATION

A. PROVISION OF BENEFITS

1 MA Organization agrees to provide enrollees in each of its employer/union-only
group health plans the basic benefits (hereinafter referred to as "basic
benefits") as required under 42 CFR Section 422.101 and, to the extent
applicable, supplemental benefits under 42 CFR Section 422.102 and as
established in the MA Organization's final benefit and price bid proposal as
approved by CMS.

2 MA Organization may swap different types of mandatory supplemental benefits
and optional supplemental benefits (as defined in 42 CFR Section 422.2)
(hereinafter referred to as "supplemental benefits") of equal actuarial value in
employer/union-only group health plans.

3 MA Organization may modify the cost sharing (e.g., coinsurance, copayments,
deductibles) of basic and supplemental benefits offered in employer/union-only
group health plans by providing a higher benefit level and/or a modified premium
to employer/union-only groups contracting with MA Organization. The uniformity
of premium, benefits, and cost-sharing requirement of 42 CFR Section
422.100(d)(2) shall not apply to such modifications. The overall value of each
modified benefit offered to employer/union-only groups must be actuarially
equivalent to the basic and/or supplemental benefit offered in the
employer/union-only group health plan and the modification must not have the
effect of denying or discouraging access to covered medically-necessary health
care items and services as set forth in 42 CFR Section 422.100(f)(2).

4 The requirements in section 1852 of the Act and 42 CFR Section 422.100(c)(l)
pertaining to the offering of benefits covered under Medicare Part A and in
section 1851 of the Act and 42 CFR Section 422.50(a)(l) pertaining to who may
enroll in an MA plan are waived for employer/union-only group health plan
enrollees who are not entitled to Medicare Part A.

[ ]  5. For employer/union-only group health plans offering non-calendar year
coverage, MA Organization may determine basic and supplemental benefits
(including deductibles, out-of-pocket limits, etc.) on a non-calendar year basis
subject to the following requirements:

[ ]  (a) Applications, bids, and other submissions to CMS must be submitted on a
calendar year basis; and

[ ]  (b) CMS payments will be determined on a calendar year basis.

[ ]  6. For employer/union-only group health plans that have a monthly
beneficiary rebate described in 42 CFR Section 422.266:

[ ]  (a) MA Organization may vary the form of rebate allocation so that the
rebates vary between employer/union groups within the plan benefit package for
an employer/union group to whom MA Organization offers the plan, with the
exception of a rebate credited toward the reduction of the Part B premium. Any
reduction of the Part B premium through crediting of the rebate must be
available to all members of the plan at the same level, regardless of the
enrollee's employer/union group affiliation; and

[ ]  (b) MA Organization must:

[ ]  (a) ensure Part B premium buy-downs are the same for all enrollees;

[ ]  (b) ensure that the total monthly rebate amount for the plan total rebates
per enrollee are uniform across employer groups in the plan and that all rebates
are accounted for and used only for the purposes provided in the Act; and

[ ]  (c) retain documentation that supports the use of all of the rebates on a
detailed basis and must provide access to this documentation in accordance with
the requirements of 42 CFR Section 422.501.

<PAGE>

B. ENROLLMENT REQUIREMENTS

1 MA Organization agrees to restrict enrollment in an employer/union-only group
health plan to those individuals eligible for the employer's/union's
employment-based group coverage.

2 MA Organization will not be subject to the requirement set forth in 42 CFR
Section 422.50 to offer the employer/union-only group health plan to all
eligible beneficiaries residing in the plan's service area.

3 If an employer/union elects to enroll individuals eligible for its
employer/union-only group health plan through a group enrollment process, MA
Organization will not be subject to the individual enrollment requirements set
forth in 42 CFR Section 422.60. MA Organization agrees that all individuals
eligible for its employer/union-only group health plan will be advised that the
employer/union contracting with MA Organization to offer an employer/union-only
group health plan (hereinafter referred to as "employer/union") intends to
enroll them into the plan through a group enrollment process unless the
individual affirmatively opts out of such enrollment. MA Organization agrees
that all such individuals will be provided this information at least 30 days
prior to the effective date of the individual's enrollment in the
employer/union-only group health plan. MA Organization agrees the information
must include a summary of benefits offered under the employer/union-only group
health plan, an explanation of how to get more information on such plan, and an
explanation of how to contact Medicare for information on other MA plans that
might be available to the individual. In addition, MA Organization agrees that
all information necessary to effectuate enrollment must be submitted
electronically to CMS, consistent with CMS instructions.

C. BENEFICIARY PROTECTIONS

1 MA Organization's employer/union-only group health plans will not be subject
to the marketing requirements set forth in 42 CFR Section 422.80.

2 CMS agrees that the disclosure requirements set forth in 42 CFR Sections
422.111 will not apply with respect to any employer/union-only group health plan
when the employer/union is subject to alternative disclosure requirements (e.g.,
the Employee Retirement Income Security Act of 1974 ("ERISA")) and fully
complies with such alternative requirements. MA Organization agrees to provide
beneficiary plan documents, including summary plan descriptions and all other
beneficiary communications that provide descriptions of the benefit offerings,
to CMS at the time of use and to current and/or potential enrollees on a timely
basis. CMS may review these documents in the event of beneficiary complaints or
for other reasons and require changes if CMS determines that such changes are
necessary.

D. SERVICE AREA

1 CMS agrees that Local employer/union-only group health plans that provide
coverage to individuals in any part of a State can offer coverage to individuals
eligible for the employer/union-only group throughout that State.

2 CMS agrees that Regional employer/union-only group health plans and
non-network Private Fee-for-Service employer/union-only group health plans may
extend coverage beyond their designated service areas to all enrollees of a
particular employer/union-only group plan, regardless of where they reside in
the nation, when the most substantial portion of the employer's employees (or in
the case of a union, the union's participants) reside in the service area where
the MA Organization, either itself or through subcontractors or other partners,
is a provider of non-group MA coverage. The MA Organization agrees to conduct an
actual review of where the substantial portion of the employer's/union's
employees/participants reside and to

<PAGE>

maintain adequate supporting documentation of such review (including the date of
such review, by whom the review was conducted, and any other relevant
documentation to substantiate the review), and to permit CMS to audit and review
such documentation.

F. PAYMENT TO MA ORGANIZATION

     MA Organization acknowledges that the risk sharing, plan entry and
     retention bonus provisions of section 1858 of the Act and 42 CFR Section
     422.458 shall not apply to Regional employer/union-only group health plans.

                                   ARTICLE III
                   RECORD RETENTION AND REPORTING REQUIREMENTS

A.   GENERAL REPORTING REQUIREMENTS

     MA Organization is not subject to the general public reporting requirements
     contained in 42 CFR Section 422.516(a) for its employer/union-only group
     plans to the extent that: (1) such information is required to be reported
     to enrollees and to the general public by other law (including ERISA or
     securities laws) or by a separate contractual agreement and (2) MA
     Organization fully complies with such

<PAGE>

             ADDENDUM TO MEDICARE MANAGED CARE CONTRACT PURSUANT TO
        SECTIONS 1860D-1 THROUGH 1860D-42 OF THE SOCIAL SECURITY ACT FOR
          THE OPERATION OF A VOLUNTARY MEDICARE PRESCRIPTION DRUG PLAN

The Centers for Medicare & Medicaid Services (hereinafter referred to as "CMS")
and TEXAS HEALTHSPRING I, LLC, a Medicare managed care organization (hereinafter
referred to as the MA-PD Sponsor) agree to amend the contract (H4513) governing
the MA-PD Sponsor's operation of a Part C plan described in Section
1851(a)(2)(A) of the Social Security Act (hereinafter referred to as "the Act")
or a Medicare cost plan to include this addendum under which the MA-PD Sponsor
shall operate a Voluntary Medicare Prescription Drug Plan pursuant to sections
1860D-1 through 1860D-42 (with the exception of section 1860D-22 and 1860D-31)
of the Act.

This addendum is made pursuant to Subpart L of 42 CFR Part 417 (in the case of
cost plan sponsors offering a Part D benefit) and Subpart K of 42 CFR Part 422
(in the case of an MA-PD Sponsor offering a Part C plan).

NOTE: For purposes of this addendum, unless otherwise noted, reference to an
"MA-PD Sponsor" or "MA-PD Plan" is deemed to include a cost plan sponsor or a MA
private fee-for-service contractor offering a Part D benefit.

A.   The MA-PD Sponsor agrees to operate one or more Medicare Voluntary
     Prescription Drug Plans as described in its application and related
     materials, including but not limited to all the attestations contained
     therein and all supplemental guidance, for Medicare approval and in
     compliance with the provisions of this addendum, which incorporates in its
     entirety the Solicitation For Applications from Prescription Drug Plans
     released on January 21, 2005 (as revised on March 9, 2005) [applicable to
     Medicare Part C contractors] or the Solicitation for Applications from Cost
     Plan Sponsors released on January 21, 2005 (as revised on March 9, 2005)
     [applicable to Medicare cost plan contractors] (hereinafter collectively
     referred to as "the addendum"). The MA-PD Sponsor also agrees to operate in
     accordance with the regulations at 42 CFR Section 423.1 through 42 CFR
     Section 423.910 (with the exception of Subparts Q, R, and S), sections
     1860D-1 through 1860D-42 (with the exception of sections 1860D-22(a) and
     1860D-31) of the Social Security Act, and the applicable solicitation
     identified above, as well as all other applicable Federal statutes,
     regulations, and policies. This addendum is deemed to incorporate any
     changes that are required by statute to be implemented during the term of
     this addendum and any regulations or policies implementing or interpreting
     such statutory provisions.

B.   CMS agrees to perform its obligations to the MA-PD Sponsor consistent with
     the regulations at 42 CFR Section 423.1 through 42 CFR Section 423.910
     (with the exception of Subparts Q, R, and S), sections 1860D-1 through
     1860D-42 (with the exception of sections 1860D- 22(a) and 1860D-31) of the
     Social Security Act, and the applicable solicitation, as well as all other
     applicable Federal statutes, regulations, and policies.

C.   CMS agrees that it will not implement, other than at the beginning of a
     calendar year, regulations under 42 CFR Part 423 that impose new,
     significant regulatory requirements on the MA-PD Sponsor. This provision
     does not apply to new requirements mandated by statute.

<PAGE>

D.   This addendum is in no way intended to supersede or modify 42 CFR, Parts
     417, 422 or 423. Failure to reference a regulatory requirement in this
     addendum does not affect the applicability of such requirements to the
     MA-PD Sponsor and CMS.

                                   ARTICLE II
                 FUNCTIONS TO BE PERFORMED BY THE MA-PD SPONSOR

A. ENROLLMENT

1 MA-PD Sponsor agrees to enroll in its MA-PD plan only Part D-eligible
beneficiaries as they are defined in 42 CFR Section 423.30(a) and who have
elected to enroll in MA-PD Sponsor's Part C or Section 1876 benefit.

2 If the MA-PD Sponsor is a cost plan sponsor, the MA-PD Sponsor acknowledges
that its Section 1876 plan enrollees are not required to elect enrollment in its
Part D plan.

B. PRESCRIPTION DRUG BENEFIT

1 MA-PD Sponsor agrees to provide the required prescription drug coverage as
defined under 42 CFR Section 423.100 and, to the extent applicable, supplemental
benefits as defined in 42 CFR Section 423.100 and in accordance with Subpart C
of 42 CFR Part 423. MA-PD Sponsor also agrees to provide Part D benefits as
described in the MA-PD Sponsor's Part D bid(s) approved each year by CMS (and in
the Attestation of Benefit Plan and Price, attached hereto).

2 MA-PD Sponsor agrees to calculate and collect beneficiary Part D premiums in
accordance with 42 CFR Sections 423.286 and 423.293.

3 If the MA-PD Sponsors is a cost plans sponsor, it acknowledge that its Part D
benefit is offered as an optional supplemental service in accordance with 42 CFR
Section 417.440(b)(2)(ii).

C. DISSEMINATION OF PLAN INFORMATION

1 MA-PD Sponsor agrees to provide the information required in 42 CFR Section
423.48.

2 MA-PD Sponsor agrees to disclose information related to Part D benefits to
beneficiaries in the manner and the form specified by CMS under 42 CFR Sections
423.128 and 423.50 and in the "Marketing Materials Guidelines for Medicare
Advantage-Prescription Drug Plans (MA-PDs) and Prescription Drug Plans (PDPs)."

3 MA-PD Sponsor certifies that all materials it submits to CMS under the File
and Use Certification authority described in the Marketing Materials Guidelines
are accurate, truthful, not misleading, and consistent with CMS marketing
guidelines.

D. QUALITY ASSURANCE/UTILIZATION MANAGEMENT

     MA-PD Sponsor agrees to operate quality assurance, cost, and utilization
     management, medication therapy management programs, and support electronic
     prescribing in accordance with Subpart D of 42 CFR Part 423.

E. APPEALS AND GRIEVANCES

     MA-PD Sponsor agrees to comply with all requirements in Subpart M of 42 CFR
     Part 423 governing coverage determinations, grievances and appeals, and
     formulary exceptions. MA-

<PAGE>

     PD Sponsor acknowledges that these requirements are separate and distinct
     from the appeals and grievances requirements applicable to the MA-PD
     Sponsor through the operation of its Part C or cost plan benefits.

F. PAYMENT TO MA-PD SPONSOR

1 MA-PD Sponsor and CMS agree that payment paid for Part D services under the
addendum will be governed by the rules in Subpart G of 42 CFR Part 423.

2 If the MA-PD Sponsor is participating in the Part D Reinsurance Payment
Demonstration, described in 70 FR 9360 (Feb. 25, 2005), it affirms that it will
not seek payment under the demonstration for services provided to employer group
enrollees.

G. BID SUBMISSION AND REVIEW

     If the MA-PD Sponsor intends to participate in the Part D program for the
     future year, MA-PD Sponsor agrees to submit a future year's Part D bid,
     including all required information on premiums, benefits, and cost-sharing,
     by the applicable due date, as provided in Subpart F of 42 CFR Part 423 so
     that CMS and the MA-PD Sponsor may conduct negotiations regarding the terms
     and conditions of the proposed bid and benefit plan renewal. MA-PD Sponsor
     acknowledges that failure to submit a timely bid under this section may
     affect the sponsor's ability to offer a Part C plan, pursuant to the
     provisions of 42 CFR Section 422.4(c).

H. COORDINATION WITH OTHER PRESCRIPTION DRUG COVERAGE

1 MA-PD Sponsor agrees to comply with the coordination requirements with State
Pharmacy Assistance Programs (SPAPs) and plans that provide other prescription
drug coverage as described in Subpart J of 42 CFR Part 423.

2 MA-PD Sponsor agrees to comply with Medicare Secondary Payer procedures as
stated in 42 CFR Section 423.462.

I. SERVICE AREA AND PHARMACY ACCESS

1 The MA-PD Sponsor agrees to provide Part D benefits in the service area for
which it has been approved by CMS to offer Part C or cost plan benefits
utilizing a pharmacy network and formulary approved by CMS that meet the
requirements of 42 CFR Section 423.120.

2 The MA-PD Sponsor agrees to ensure adequate access to Part D-covered drugs at
out-of-network pharmacies according to 42 CFR Section 423.124.

3 MA-PD Sponsor agrees to provide benefits by means of point-of-service systems
to adjudicate prescription drug claims in a timely and efficient manner in
compliance with CMS standards, except when necessary to provide access in
underserved areas, I/T/U pharmacies (as defined in 42 CFR Section 423.100), and
long-term care pharmacies (as defined in 42 CFR Section 423.100).

4 MA-PD Sponsor agrees to contract with any pharmacy that meets the MA-PD
Sponsor's reasonable and relevant standard terms and conditions. If MA-PD
Sponsor has demonstrated that it historically fills 98% or more of its
enrollees' prescriptions at pharmacies owned and operated by the MA-PD Sponsor
(or presents compelling circumstances that prevent the sponsor from meeting the
98% standard or demonstrates that its Part D plan design will enable the sponsor
to meet the 98% standard during the contract year), this provision does not
apply to MA-PD Sponsor's plan.

5 The provisions of 42 CFR Section 423.120(a) concerning the TRICARE retail
pharmacy access standard do not apply to MA-PD Sponsor if the Sponsor has
demonstrated to CMS that it

<PAGE>

historically fills more than 50% of its enrollees' prescriptions at pharmacies
owned and operated by the MA-PD Sponsor. MA-PD Sponsors excused from meeting the
TRICARE standard are required to demonstrate retail pharmacy access that meets
the requirements of 42 CFR Section 422.112 for a Part C contractor and 42 CFR
Section 417.416(e) for a cost plan contractor.

J. COMPLIANCE PLAN/PROGRAM INTEGRITY

     MA-PD Sponsor agrees that it will develop and implement a compliance plan
     that applies to its Part D-related operations, consistent with 42 CFR
     Section 423.504(b)(4)(vi).

K. LOW-INCOME SUBSIDY

     MA-PD Sponsor agrees that it will participate in the administration of
     subsidies for low-income individuals according to Subpart P of 42 CFR Part
     423.

L. BENEFICIARY FINANCIAL PROTECTIONS

     The MA-PD Sponsor agrees to afford its enrollees protection from liability
     for payment of fees that are the obligation of the MA-PD Sponsor in
     accordance with 42 CFR Section 423.505(g).

M. RELATIONSHIP WITH RELATED ENTITIES, CONTRACTORS, AND SUBCONTRACTORS

1 The MA-PD Sponsor agrees that it maintains ultimate responsibility for
adhering to and otherwise fully complying with all terms and conditions of this
addendum.

2 The MA-PD Sponsor shall ensure that any contracts or agreements with
subcontractors or agents performing functions on the MA-PD Sponsor's behalf
related to the operation of the Part D benefit are in compliance with 42 CFR
Section 423.505(i).

N. CERTIFICATION OF DATA THAT DETERMINE PAYMENT

     MA-PD Sponsor must provide certifications in accordance with 42 CFR
     Section 423.505(k).

                                   ARTICLE III
                   RECORD RETENTION AND REPORTING REQUIREMENTS

A. MAINTENANCE OF RECORDS

     MA-PD Sponsor agrees to maintain records and provide access in accordance
     with 42 CFR Sections 423.504(d) and 505(d) and (e).

B. GENERAL REPORTING REQUIREMENTS

     The MA-PD Sponsor agrees to submit to information to CMS according to 42
     CFR Sections 423.505(f), 423.514, and the "Final Medicare Part D Reporting
     Requirements," a document issued by CMS and subject to modification each
     program year.

<PAGE>

C. CMS License For Use of Plan Formulary

     PDP Sponsor agrees to submit to CMS each plan's formulary information,
     including any changes to its formularies, and hereby grants to the
     Government [, and any person or entity who might receive the formulary from
     the Government,] a non-exclusive license to use all or any portion of the
     formulary for any purpose related to the administration of the Part D
     program, including without limitation publicly distributing, displaying,
     publishing or reconfiguration of the information in any medium, including
     www.medicare.gov, and by any electronic, print or other means of
     distribution.

                                   ARTICLE IV
                       HIPAA TRANSACTIONS/PRIVACY/SECURITY

A.   MA-PD Sponsor agrees to comply with the confidentiality and enrollee record
     accuracy requirements specified in 42 CFR Section 423.136.

B.   MA-PD Sponsor agrees to enter into a business associate agreement with the
     entity with which CMS has contracted to track Medicare beneficiaries' true
     out-of-pocket costs.

                                    ARTICLE V
                            ADDENDUM TERM AND RENEWAL

A.   TERM OF ADDENDUM This addendum is effective from the date of CMS'
     authorized representative's signature through December 31, 2006. This
     addendum shall be renewable for successive one-year periods thereafter
     according to 42 CFR Section 423.506. MA-PD Sponsor shall not conduct Part
     D-related marketing activities prior to October 1, 2005 and shall not
     process enrollment applications prior to November 15,2005. MA-PD Sponsor
     shall begin delivering Part D benefit services on January 1,2006.

B.   QUALIFICATION TO RENEW ADDENDUM

     1.   In accordance with 42 CFR Section 423.507, the MA-PD Sponsor will be
          determined qualified to renew this addendum annually only if--

[ ]  (a) CMS informs the MA-PD Sponsor that it is qualified to renew its
addendum; and

[ ]  (b) The MA-PD Sponsor has not provided CMS with a notice of intention not
to renew in accordance with Article VII of this addendum.

     2.   Although MA-PD Sponsor may be determined qualified to renew its
          addendum under this Article, if the MA-PD Sponsor and CMS cannot reach
          agreement on the Part D bid under Subpart F of 42 CFR Part 423, no
          renewal takes place, and the failure to reach agreement is not subject
          to the appeals provisions in Subpart N of 42 CFR Parts 422 or 423.
          (Refer to Article XI for consequences of non-renewal on the Part C
          contract and the ability to enter into a Part C contract.)

<PAGE>

                                   ARTICLE VI
                             NONRENEWAL OF ADDENDUM

A. NONRENEWAL BY THE MA-PD SPONSOR

1 MA-PD Sponsor may non-renew this addendum in accordance with 42 CFR423.507(a).

2 If the MA-PD Sponsor non-renews this addendum under this Article, CMS cannot
enter into a Part D addendum with the organization for 2 years unless there are
special circumstances that warrant special consideration, as determined by CMS.

B. NONRENEWAL BY CMS

     CMS may non-renew this addendum under the rules of 42 CFR 423.507(b).
     (Refer to Article X for consequences of non-renewal on the Part C contract
     and the ability to enter into a Part C contract.)

                                   ARTICLE VII
            MODIFICATION OR TERMINATION OF ADDENDUM BY MUTUAL CONSENT

     This addendum may be modified or terminated at any time by written mutual
     consent in

                                  ARTICLE VIII
                         TERMINATION OF ADDENDUM BY CMS

CMS may terminate this addendum in accordance with 42 CFR 423.509. (Refer to
Article X for consequences of non-renewal on the Part C contract and the ability
to enter into a Part C contract.)

                                   ARTICLE IX
                  TERMINATION OF ADDENDUM BY THE MA-PD SPONSOR

A.   The MA-PD Sponsor may terminate this addendum only in accordance with 42
     CFR 423.510.

B.   CMS will not enter into a Part D addendum with an organization that has
     terminated its addendum within the preceding 2 years unless there are
     circumstances that warrant special consideration, as determined by CMS.

C.   If the addendum is terminated under section A of this Article, the MA-PD
     Sponsor must ensure the timely transfer of any data or files. (Refer to
     Article X for consequences of non- renewal on the Part C contract and the
     ability to enter into a Part C contract.)

<PAGE>

                                    ARTICLE X
     RELATIONSHIP BETWEEN ADDENDUM AND PART C CONTRACT OR 1876 COST CONTRACT

A.   MA-PD Sponsor acknowledges that, if it is a Medicare Part C contractor, the
     termination or nonrenewal of this addendum by either party may require CMS
     to terminate or non-renew the Sponsor's Part C contract in the event that
     such non-renewal or termination prevents the MA-PD Sponsor from meeting the
     requirements of 42 CFR Section 422.4(c), in which case the Sponsor must
     provide the notices specified in this contract, as well as the notices
     specified under Subpart K of 42 CFR Part 422. MA-PD Sponsor also
     acknowledges that Article X.B. of this addendum may prevent the sponsor
     from entering into a Part C contract for two years following an addendum
     termination or non-renewal where such non-renewal or termination prevents
     the MA-PD Sponsor from meeting the requirements of 42 CFR Section 422.4(c).

B.   The termination of this addendum by either party shall not, by itself,
     relieve the parties from their obligations under the Part C or cost plan
     contracts to which this document is an addendum.

C.   In the event that the MA-PD Sponsor's Part C or cost plan contract (as
     applicable) is terminated or nonrenewed by either party, the provisions of
     this addendum shall also terminate. In such an event, the MA-PD Sponsor and
     CMS shall provide notice to enrollees and the public as described in this
     contract as well as 42 CFR Part 422, Subpart K or 42 CFR Part 417, Subpart
     K, as applicable.

                                   ARTICLE XI
                             INTERMEDIATE SANCTIONS

     The MA-PD Sponsor shall be subject to sanctions and civil monetary
     penalties, consistent with Subpart O of 42 CFR Part 423.

                                   ARTICLE XII
                                  SEVERABILITY

     Severability of the addendum shall be in accordance with 42 CFR
     Section 423.504(e).

                                  ARTICLE XIII
                                  MISCELLANEOUS

A.   DEFINITIONS: Terms not otherwise defined in this addendum shall have the
     meaning given such terms at 42 CFR Part 423 or, as applicable, 42 CFR Part
     422 or Part 417.

<PAGE>

B.   ALTERATION TO ORIGINAL ADDENDUM TERMS: The MA-PD Sponsor agrees that it has
     not altered in any way the terms of the MA-PD addendum presented for
     signature by CMS. MA-PD Sponsor agrees that any alterations to the original
     text the MA-PD Sponsor may make to this addendum shall not be binding on
     the parties.

C.   ADDITIONAL CONTRACT TERMS: The MA-PD Sponsor agree to include in this
     addendum other terms and conditions in accordance with 42 CFR
     Section 423.505(j).

D.   CMS APPROVAL TO BEGIN MARKETING AND ENROLLMENT ACTIVITIES: The MA-PD
     Sponsor agrees that it must complete CMS operational requirements related
     to its Part D benefit prior to receiving CMS approval to begin MA-PD plan
     marketing activities relating to its Part D benefit. Such activities
     include, but are not limited to, establishing and successfully testing
     connectivity with CMS systems to process enrollment applications (or
     contracting with an entity qualified to perform such functions on MA-PD
     Sponsor's behalf) and successfully demonstrating the capability to submit
     accurate and timely price comparison data. To establish and successfully
     test connectivity, the PDP Sponsor must, 1) establish and test physical
     connectivity to the CMS data center, 2) acquire user identifications and
     passwords, 3) receive, store, and maintain data necessary to perform
     enrollments and send and

In witness whereof, the parties hereby execute this contract.

FOR THE PDP SPONSOR

JEFF ROTHENBERGER                       SR. VP & CORPORATE COO
-------------------------------------   Title
Printed Name


/s/ Jeff Rothenberger                   9/7/05
-------------------------------------   Date
Signature

TEXAS HEALTHSPRING I, LLC
Organization

2900 NORTH LOOP WEST, SUITE 1300, HOUSTON, TX 77292
Address

FOR THE CENTERS FOR MEDICARE & MEDICAID SERVICES


-------------------------------------   ----------------------------------------
Robert Donnelly                         Date
Director Medicare Drug Benefit Group
Center for Beneficiary Choices

<PAGE>

       PART C/D BENEFIT PLAN(S) DESCRIPTION TO BE ATTACHED TO MA CONTRACT

             SECTION 1876/PART D OPTIONAL SUPPLEMENTAL BENEFIT PLAN
               DESCRIPTION TO BE ATTACHED TO SECTION 1876 CONTRACT

<PAGE>

            Medicare Advantage Attestation of Benefit Plan and Price

                            TEXAS HEALTHSPRING I, LLC

                                      H4513

                                Date: 09/06/2005

I attest that the following plan numbers as established in the final Plan
Benefit Package (PBP) will be operated by the above-stated organization and made
available to eligible Medicare beneficiaries in the approved service area during
program year 2006.

<TABLE>
<CAPTION>
                                                                                       CMS
PLAN   SEGMENT                            PLAN   TRANSACTION      MA      PART D    APPROVAL     EFFECTIVE
 ID       ID     VERSION     PLAN NAME    TYPE      TYPE       PREMIUM   PREMIUM      DATE         DATE
----   -------   -------   ------------   ----   -----------   -------   -------   ----------   ----------
<S>    <C>       <C>       <C>            <C>    <C>           <C>       <C>       <C>          <C>
                               Texas
                           HealthSpring
 001      0         5          Metro       HMO     Renewal       0.00      0.00    08/31/2005   01/01/2006
                             Advantage
                               Plus

                               Texas
 006      0         5      HealthSpring    HMO     Renewal       0.00     19.00    08/31/2005   01/01/2O06
                               Plus

                               Texas
 009      0         4      HealthSpring    HMO     Renewal       0.00       N/A    08/30/2005   01/01/2006
                            True Choice

                               Texas
 010      0         4      HealthSpring    HMO     Renewal       0.00     16.00    08/31/2005   01/01/2006
                            Total Care

                               Texas
 014      0         5      HealthSpring    HMO     Renewal       0.00     18.50    08/31/2005   01/01/2006
                             Advantage

                               Texas
 015      0         5      HealthSpring    HMO     Renewal       0.00     14.49    08/31/2005   01/01/2006
                           Special Care
</TABLE>


/s/ Murray Blackshear                   9/7/05
-------------------------------------   DATE:
CEO:
Murray Blackshear
Chief Executive Officer (CEO)
2900 North Loop West Suite 1300
Suite 200 West
Houston, TX 77092
832-553-3303


/s/ Greg Allen                          9/6/05
-------------------------------------   DATE:
CFO:
Greg Allen
Chief Financial Officer


             Page 1 - TEXAS HEALTHSPRING I, LLC - H4513 - 09/06/2005

<PAGE>

2900 North Loop West Suite 1300
Houston, TX 77092
832-553-3300


             Page 2 - TEXAS HEALTHSPRING I, LLC - H4513 - 09/06/2005

<PAGE>

            Medicare Advantage Attestation of Benefit Plan and Price

                            TEXAS HEALTHSPRING I, LLC

                                      H4513

                                Date: 09/06/2005

I attest that the following plan numbers as established in the final Plan
Benefit Package (PBP) will be operated by the above-stated organization and made
available to eligible Medicare beneficiaries in the approved service area during
program year 2006.

<TABLE>
<CAPTION>
                                                                                      CMS
PLAN   SEGMENT                            PLAN   TRANSACTION      MA      PART D    APPROVAL     EFFECTIVE
 ID       ID     VERSION     PLAN NAME    TYPE       TYPE      PREMIUM   PREMIUM      DATE         DATE
----   -------   -------   ------------   ----   -----------   -------   -------   ----------   ----------
<S>    <C>       <C>       <C>            <C>    <C>           <C>       <C>       <C>          <C>
                               Texas
 802      0         2      HealthSpring    HMO     Renewal       0.00      N/A     08/30/2005   01/01/2006
                              Retiree
                              Choice
</TABLE>


/s/ Murray Blackshear                   9/7/05
-------------------------------------   DATE:
CEO:
Murray Blackshear
Chief Executive Officer (CEO)
2900 North Loop West Suite 1300
Suite 200 West
Houston, TX 77092
832-553-3303


/s/ Greg Allen                          9/6/05
-------------------------------------   DATE:
CFO:
Greg Allen
Chief Financial Officer
Houston, TX 77092
832-553-3300


             Page 1 - TEXAS HEALTHSPRING I, LLC - H4513 - 09/06/2005