<PAGE>   1
                                                                     EXHIBIT 99

                               CONSUMERS GAS GROUP
                      MANAGEMENT'S DISCUSSION AND ANALYSIS


In 1995, CMS Energy issued a total of 7.62 million shares of Class G Common
Stock. This class of Common Stock reflects the separate performance of the gas
distribution, storage and transportation businesses conducted by Consumers and
Michigan Gas Storage Company, a subsidiary of Consumers (collectively, Consumers
Gas Group). Accordingly, this MD&A should be read along with the MD&A in the
1998 Annual Report of CMS Energy included and incorporated by reference herein.

CMS Energy is the parent holding company of Consumers and CMS Enterprises
Company. Consumers, a combination electric and gas utility company serving the
Lower Peninsula of Michigan, is the principal subsidiary of CMS Energy. For
further information regarding the businesses of CMS Energy, including the nature
and issuance of Class G Common Stock, see the MD&A of CMS Energy.


RESULTS OF OPERATIONS

<TABLE>
<CAPTION>
                                                                                     In Millions
------------------------------------------------------------------------------------------------
March 31                                                      1999           1998         Change
------------------------------------------------------------------------------------------------
<S>                                                         <C>            <C>            <C>   
Three Months Ended                                          $    39        $    36        $    3
Twelve Months Ended                                         $    55        $    57        $   (2)
================================================================================================
</TABLE>

The increase in net income for the three months ended March 31, 1999 compared to
the same 1998 period reflects increased gas deliveries due to colder
temperatures during the 1999 heating season. Partially offsetting the increase
was the benefit resulting from a one-time accounting change for property taxes
in the first quarter of 1998. The recognition of property tax expense was
changed from expensing on a calendar year basis to a fiscal year basis which
resulted in a benefit of $18 million ($12 million after-tax). The decrease in
earnings for the twelve months ended March 31, 1999 compared to the same 1998
period reflects the change in accounting for property taxes implemented in March
1998 as discussed above and an increase in depreciation, partially offset by a
decrease in the cost of gas.


GAS ISSUES

For a discussion of Consumers Gas Group operating issues, see Consumers Gas
Group Results of Operations - Uncertainties in CMS Energy's MD&A.


CASH POSITION, INVESTING AND FINANCING

OPERATING ACTIVITIES: Consumers Gas Group's cash requirements are met by its
operating and financing activities. Consumers Gas Group's cash from operations
is derived mainly from Consumers' sale and transportation of natural gas. Cash
from operations for the first quarter of 1999 and 1998 totaled $188 million and
$159 million, respectively. The $29 million increase primarily reflects
increased earnings and depreciation, coupled with the absence of the 1998
cumulative effect of the property tax accounting change.

                                        1

<PAGE>   2



Consumers Gas Group uses its operating cash primarily to maintain and expand its
gas utility transmission and distribution systems, to retire portions of its
long-term debt, and to pay dividends.

INVESTING ACTIVITIES: Cash used in investing activities for the first quarter of
1999 and 1998 totaled $20 million and $22 million, respectively. The $2 million
decrease in cash used primarily reflects decreased capital expenditures.

FINANCING ACTIVITIES: Cash used in financing activities during the first quarter
of 1999 and 1998 totaled $166 million and $133 million, respectively. The $33
million increase in cash used primarily reflects a decrease in the proceeds from
senior notes, partially offset by a decrease in the retirement of bonds and
other long-term debt.

OTHER INVESTING AND FINANCING MATTERS: Consumers has an agreement permitting the
sale of certain accounts receivable for up to $500 million. At March 31, 1999,
receivables sold totaled $344 million. Consumers Gas Group's attributed portion
of these receivables sold totaled $154 million. Accounts receivable and accrued
revenue in the Balance Sheets have been reduced to reflect receivables sold. For
further information, see CMS Energy's Note 3.


CAPITAL EXPENDITURES

CMS Energy estimates the following capital expenditures for Consumers Gas Group,
including new lease commitments, over the next three years. These estimates are
prepared for planning purposes and are subject to revision.

<TABLE>
<CAPTION>
                                                                                   In Millions
-----------------------------------------------------------------------------------------------
Years Ended December 31                               1999              2000              2001
-----------------------------------------------------------------------------------------------
<S>                                                  <C>               <C>               <C>   
Gas utility (a)                                      $  120            $  120            $  118
Michigan Gas Storage                                      3                 3                 2
                                                     ------------------------------------------

                                                     $  123            $  123            $  120
===============================================================================================
</TABLE>

(a) Includes a portion of anticipated capital expenditures common to Consumers'
gas and electric utility businesses.

Consumers Gas Group expects that cash from operations and the ability to access
debt markets will provide necessary working capital and liquidity to fund future
capital expenditures, required debt payments, and other cash needs in the
foreseeable future. For further information regarding forward-looking
information, see the Consumers Gas Group Outlook discussion in CMS Energy's
MD&A.


YEAR 2000 COMPUTER MODIFICATIONS

For a discussion of Consumers Gas Group's year 2000 computer modification
efforts, see Year 2000 Computer Modifications in CMS Energy's MD&A.



                                        2

<PAGE>   3


FORWARD-LOOKING STATEMENTS

For cautionary statements relating to Consumers Gas Group's forward-looking
information, see Forward- Looking Statements in CMS Energy's MD&A.






























                                       3
<PAGE>   4

                               CONSUMERS GAS GROUP
                              STATEMENTS OF INCOME
                                   (UNAUDITED)

<TABLE>
<CAPTION>
                                                          THREE MONTHS ENDED      TWELVE MONTHS ENDED
MARCH 31                                                   1999        1998        1999         1998
-----------------------------------------------------------------------------------------------------
                                                                In Millions, Except Per Share Amounts
<S>                                                      <C>         <C>         <C>          <C>    
OPERATING REVENUE                                        $   506     $   429     $ 1,128      $ 1,135
-----------------------------------------------------------------------------------------------------
Operating Expenses
  Operation
    Cost of gas sold                                         306         264         606          645
    Other                                                     47          46         178          182
                                                         --------------------------------------------
                                                             353         310         784          827
  Maintenance                                                  8           9          31           34
  Depreciation, depletion and amortization                    44          36         105           90
  General taxes                                               23          20          58           54
                                                         --------------------------------------------
                                                             428         375         978        1,005
-----------------------------------------------------------------------------------------------------

PRETAX OPERATING INCOME                                       78          54         150          130
-----------------------------------------------------------------------------------------------------

OTHER INCOME (DEDUCTIONS)                                      2           -          (3)         (2)
-----------------------------------------------------------------------------------------------------
FIXED CHARGES
  Interest on long-term debt                                   7           7          28           28
  Other interest                                               4           4          15           14
  Preferred dividends                                          1           1           4            5
                                                         --------------------------------------------
                                                              12          12          47           47
-----------------------------------------------------------------------------------------------------

INCOME BEFORE INCOME TAXES                                    68          42         100           81

INCOME TAXES                                                  29          18          45           36
                                                         --------------------------------------------


NET INCOME BEFORE CUMULATIVE EFFECT OF CHANGE IN
  ACCOUNTING PRINCIPLE                                        39          24          55           45
CUMULATIVE EFFECT OF CHANGE IN ACCOUNTING FOR
  PROPERTY TAXES, NET OF $6 TAX                                -          12           -           12
                                                         --------------------------------------------

NET INCOME                                               $    39     $    36     $    55      $    57
=====================================================================================================

NET INCOME ATTRIBUTABLE TO CMS ENERGY SHAREHOLDERS
  THROUGH RETAINED INTEREST                              $    29     $    27     $    41      $    42
-----------------------------------------------------------------------------------------------------
NET INCOME ATTRIBUTABLE TO CLASS G SHAREHOLDERS          $    10     $     9     $    14      $    15
-----------------------------------------------------------------------------------------------------

AVERAGE CLASS G COMMON SHARES OUTSTANDING                      8           8           8            8
-----------------------------------------------------------------------------------------------------
BASIC AND DILUTED EARNINGS PER AVERAGE CLASS G
  COMMON SHARE BEFORE CHANGE IN ACCOUNTING PRINCIPLE     $  1.19     $   .73     $  1.68      $  1.40
-----------------------------------------------------------------------------------------------------

CUMULATIVE EFFECT OF CHANGE IN ACCOUNTING PRINCIPLE,
  NET OF TAX, PER AVERAGE CLASS G COMMON SHARE           $     -     $   .36     $     -      $   .36
-----------------------------------------------------------------------------------------------------
BASIC AND DILUTED EARNINGS PER AVERAGE CLASS G
  COMMON SHARE                                           $  1.19     $  1.09     $  1.68      $  1.76
-----------------------------------------------------------------------------------------------------

DIVIDEND DECLARED PER CLASS G COMMON SHARE               $  .325     $   .31     $ 1.285      $ 1.225
=====================================================================================================
</TABLE>

THE ACCOMPANYING CONDENSED NOTES ARE AN INTEGRAL PART OF THESE STATEMENTS.

                                        4

<PAGE>   5
                               CONSUMERS GAS GROUP
                            STATEMENTS OF CASH FLOWS
                                   (UNAUDITED)

<TABLE>
<CAPTION>
                                                                                     THREE MONTHS ENDED TWELVE MONTHS ENDED
MARCH 31                                                                              1999       1998       1999       1998
---------------------------------------------------------------------------------------------------------------------------
                                                                                                                In Millions
<S>                                                                                  <C>        <C>        <C>        <C>  
CASH FLOWS FROM OPERATING ACTIVITIES
  Net income                                                                         $  39      $  36      $  55      $  57
    Adjustments to reconcile net income to net cash
      provided by operating activities
        Depreciation, depletion and amortization                                        44         36        105         90
        Capital lease and other amortization                                             1          1          2          4
        Deferred income taxes and investment tax credit                                  2          4         14          5
        Cumulative effect of accounting change                                           -        (18)         -        (18)
        Other                                                                            -          -          -          1
        Changes in other assets and liabilities                                        102        100        (37)        86
                                                                                     --------------------------------------
          Net cash provided by operating activities                                    188        159        139        225
---------------------------------------------------------------------------------------------------------------------------

CASH FLOWS FROM INVESTING ACTIVITIES
  Capital expenditures (excludes assets placed under capital lease)                    (18)       (20)      (109)      (111)
  Cost to retire property, net                                                          (2)        (2)        (9)        (9)
  Proceeds from the sale of property                                                     -          -          4          -
  Other                                                                                  -          -          2          1
                                                                                     --------------------------------------
          Net cash used in investing activities                                        (20)       (22)      (112)      (119)
---------------------------------------------------------------------------------------------------------------------------

CASH FLOWS FROM FINANCING ACTIVITIES
  Increase (decrease) in notes payable, net                                           (124)      (119)        (6)       (17)
  Return of CMS Energy stockholders' contribution                                      (35)       (16)       (51)       (55)
  Payment of common stock dividends                                                    (11)       (10)       (43)       (40)
  Retirement of bonds and other long-term debt                                          (1)       (73)       (88)       (83)
  Repayment of bank loans                                                                -        (10)         -        (11)
  Payment of capital lease obligations                                                   -         (1)        (5)        (4)
  Retirement of preferred stock                                                          -          -          -        (26)
  Proceeds from long-term note and bank loans                                            4          -          4         25
  Issuance of common stock                                                               1          2          5          8
  Proceeds from senior notes                                                             -         94        118         94
  Contribution from CMS Energy stockholders                                              -          -         37          -
                                                                                     --------------------------------------
          Net cash used in financing activities                                       (166)      (133)       (29)      (109)
---------------------------------------------------------------------------------------------------------------------------

NET INCREASE (DECREASE) IN CASH AND TEMPORARY CASH INVESTMENTS                           2          4         (2)        (3)

CASH AND TEMPORARY CASH INVESTMENTS, BEGINNING OF PERIOD                                 2          2          6          9
                                                                                     --------------------------------------
 
CASH AND TEMPORARY CASH INVESTMENTS, END OF PERIOD                                   $   4      $   6      $   4      $   6
===========================================================================================================================

OTHER CASH FLOW ACTIVITIES AND NON-CASH INVESTING AND FINANCING ACTIVITIES WERE:
CASH TRANSACTIONS
  Interest paid (net of amounts capitalized)                                         $   6      $  13      $  31      $  43
  Income taxes paid (net of refunds)                                                     -          1         27         41
NON-CASH TRANSACTIONS
  ASSETS PLACED UNDER CAPITAL LEASE                                                  $   -      $   1      $   4      $   3
===========================================================================================================================
</TABLE>

All highly liquid investments with an original maturity of three months or less 
are considered cash equivalents.

THE ACCOMPANYING CONDENSED NOTES ARE AN INTEGRAL PART OF THESE STATEMENTS.


                                        5

<PAGE>   6


                               CONSUMERS GAS GROUP
                                 BALANCE SHEETS

<TABLE>
<CAPTION>
ASSETS                                                                     MARCH 31                    MARCH 31
                                                                               1999    DECEMBER 31         1998
                                                                        (UNAUDITED)           1998  (UNAUDITED)
---------------------------------------------------------------------------------------------------------------
                                                                                                    In Millions
<S>                                                                       <C>         <C>           <C>        
PLANT AND PROPERTY (AT COST)
  Plant and property                                                      $   2,374   $     2,360   $     2,346
  Less accumulated depreciation, depletion and amortization                   1,292         1,252         1,264
                                                                          -------------------------------------
                                                                              1,082         1,108         1,082
  Construction work-in-progress                                                  33            31            27
                                                                          -------------------------------------
                                                                              1,115         1,139         1,109
---------------------------------------------------------------------------------------------------------------

CURRENT ASSETS
  Cash and temporary cash investments at cost, which approximates market          4             2             6
  Accounts receivable and accrued revenue, less allowances
    of $2, $3, and $3, respectively                                             155            75            64
  Inventories at average cost
    Gas in underground storage                                                   82           219            79
    Materials and supplies                                                        6             6             7
  Deferred income taxes                                                           -             -             3
  Prepayments and other                                                          38            51            55
                                                                          -------------------------------------
                                                                                285           353           214
---------------------------------------------------------------------------------------------------------------


NON-CURRENT ASSETS
  Postretirement benefits                                                       128           131           140
  Deferred income taxes                                                          37            16            10
  Other                                                                          89            87            62
                                                                          -------------------------------------
                                                                                254           234           212
                                                                          -------------------------------------
TOTAL ASSETS                                                              $   1,654   $     1,726   $     1,535
===============================================================================================================
</TABLE>

                                        6

<PAGE>   7





<TABLE>
<CAPTION>
STOCKHOLDERS' INVESTMENT AND LIABILITIES                                MARCH 31                        MARCH 31
                                                                            1999     DECEMBER 31            1998
                                                                      (UNAUDITED)           1998      (UNAUDITED)
----------------------------------------------------------------------------------------------------------------
                                                                                                     In Millions
<S>                                                                   <C>            <C>             <C>        
CAPITALIZATION
  Common stockholders' equity                                         $      373     $       379     $       370
  Preferred stock                                                             53              52              52
  Long-term debt                                                             465             454             401
  Non-current portion of capital leases                                       13              14              16
                                                                      ------------------------------------------
                                                                             904             899             839
----------------------------------------------------------------------------------------------------------------

CURRENT LIABILITIES
  Current portion of long-term debt and capital leases                        38              37              62
  Accounts payable                                                            99              92              70
  Accrued taxes                                                               69              61              76
  Accrued refunds                                                             11               9               8
  Accrued interest                                                             7               8               2
  Deferred income taxes                                                        5               4               -
  Notes payable                                                                -             118               -
  Other                                                                       52              47              45
                                                                      ------------------------------------------ 
                                                                             281             376             263
----------------------------------------------------------------------------------------------------------------

NON-CURRENT LIABILITIES
  Regulatory liabilities for income taxes, net                               212             189             178
  Postretirement benefits                                                    155             159             166
  Deferred investment tax credit                                              24              25              25
  Other                                                                       78              78              64
                                                                      ------------------------------------------
                                                                             469             451             433
                                                                      ------------------------------------------ 
COMMITMENTS AND CONTINGENCIES (NOTE 4)

TOTAL STOCKHOLDERS' INVESTMENT AND LIABILITIES                        $    1,654     $     1,726     $     1,535
================================================================================================================
</TABLE>

THE ACCOMPANYING CONDENSED NOTES ARE AN INTEGRAL PART OF THESE STATEMENTS.

                                       7

<PAGE>   8


                               CONSUMERS GAS GROUP
                    STATEMENTS OF COMMON STOCKHOLDERS' EQUITY
                                   (UNAUDITED)

<TABLE>
<CAPTION>
                                                                  THREE MONTHS ENDED         TWELVE MONTHS ENDED
MARCH 31                                                           1999         1998           1999         1998
----------------------------------------------------------------------------------------------------------------
                                                                                                     In Millions
<S>                                                               <C>          <C>           <C>           <C>  
COMMON STOCK
  At beginning and end of period                                  $ 184        $ 184         $  184        $ 184
----------------------------------------------------------------------------------------------------------------
OTHER PAID-IN CAPITAL
  At beginning of period                                            113          102             88          135
  Common stock issued                                                 1            2              5            8
  CMS Energy stockholders' contribution                               -            -             37            -
  Return of CMS Energy stockholders' contribution                   (35)         (16)           (51)         (55)
                                                                  ----------------------------------------------
    At end of period                                                 79           88             79           88
----------------------------------------------------------------------------------------------------------------


RETAINED EARNINGS
  At beginning of period                                             82           72             98           81
  Net income                                                         39           36             55           57
  Common stock dividends declared                                   (11)         (10)           (43)         (40)
                                                                  ----------------------------------------------
    At end of period                                                110           98            110           98
                                                                  ----------------------------------------------

TOTAL COMMON STOCKHOLDERS' EQUITY                                 $ 373        $ 370         $  373        $ 370
================================================================================================================
</TABLE>

THE ACCOMPANYING CONDENSED NOTES ARE AN INTEGRAL PART OF THESE STATEMENTS.




                                       8

<PAGE>   9


                               CONSUMERS GAS GROUP
                     CONDENSED NOTES TO FINANCIAL STATEMENTS


1:   CORPORATE STRUCTURE

CMS Energy is the parent holding company of Consumers and Enterprises.
Consumers, a combination electric and gas utility company serving the Lower
Peninsula of Michigan, is the principal subsidiary of CMS Energy. For further
information regarding the businesses of CMS Energy, see the Notes to
Consolidated Financial Statements of CMS Energy included and incorporated by
reference herein.

CMS Energy has issued shares of Class G Common Stock. This class of Common Stock
reflects the separate performance of the gas distribution, storage and
transportation businesses conducted by Consumers and Michigan Gas Storage
Company, a subsidiary of Consumers (collectively, Consumers Gas Group). For
further information regarding the nature and issuance of the Class G Common
Stock, see Note 4 to the Consolidated Financial Statements of CMS Energy
included and incorporated by reference herein.

These Financial Statements and their related Notes should be read along with the
Financial Statements and Notes contained in the 1998 Annual Report of CMS Energy
that includes the Report of Independent Public Accountants, included and
incorporated by reference herein.


2:   EARNINGS PER SHARE AND DIVIDENDS

EARNINGS PER SHARE AND DIVIDENDS: Basic and diluted earnings per share for the
three month period ended March 31, 1999 and March 31, 1998, reflect the
performance of Consumers Gas Group. The earnings attributable to Class G Common
Stock and the related amounts per share are computed by considering the weighted
average number of shares of Class G Common Stock outstanding.

Earnings attributable to outstanding Class G Common Stock are equal to Consumers
Gas Group's net income multiplied by a fraction; the numerator is the weighted
average number of Outstanding Shares during the period, and the denominator is
the weighted average number of Outstanding Shares and Retained Interest Shares
during the period. The earnings attributable to Class G Common Stock on a per
share basis, for the three months ended March 31, 1999 and 1998, are based on
25.6 percent, 25.2 percent of the income of Consumers Gas Group, respectively.

In February 1999, CMS Energy declared and paid dividends of $.325 per share on
Class G Common Stock. In April 1999, the Board of Directors declared a quarterly
divdend of $.325 per share on Class G Common Stock, payable in May of 1999.


3:   SHORT-TERM FINANCINGS AND CAPITALIZATION

SHORT-TERM FINANCINGS:  Consumers' short-term financings are discussed in the 
Consolidated Financial Statements of CMS Energy Note 3 included and incorporated
by reference herein.


                                        9

<PAGE>   10


Consumers generally manages its short-term financings on a centralized
consolidated basis. The portion of receivables sold attributable to Consumers
Gas Group at March 31, 1999 and 1998, is estimated by management to be $154
million and $150 million, respectively. Accounts receivable and accrued revenue
in the balance sheets have been reduced to reflect receivables sold. The
portions of short-term debt and receivables sold attributable to Consumers Gas
Group reflect the high utilization of short-term borrowing to finance the
purchase of gas for storage in the summer and fall periods. The allocation of
short-term financings and related interest charges to Consumers Gas Group
generally follows the ratio of gas utility assets to total Consumers' assets.
Additionally, the carrying costs for Consumers' sales of certain of its accounts
receivable under its trade receivable purchase and sale agreement generally are
allocated to Consumers Gas Group based on the ratio of customer revenues
contributed by Consumers' gas customers to total Consumers' revenue. As a result
of the centralized management of short-term financing, the amounts allocated to
Consumers Gas Group are further adjusted in both the seasonal gas inventory
build-up period (second and third quarters) and the high seasonal gas sales
period (first and fourth quarters) to more closely reflect the higher short-term
financing requirements of the inventory build-up period and conversely the lower
financing requirements during the higher sales periods. Management believes
these allocations to be reasonable.

CAPITAL STOCK AND LONG-TERM DEBT: Consumers Gas Group's capital stock and
long-term debt, including debt resulting from the sale of Trust Preferred
Securities, have been allocated based on the ratio of gas utility assets
(including common assets attributed to the gas utility segment) to total
Consumers' assets. Management believes these measurements are reasonable. For
information regarding the long-term debt and capital stock of CMS Energy and
Consumers, see Note 3 to the Consolidated Financial Statements of CMS Energy
included and incorporated by reference herein.


4:   COMMITMENTS AND CONTINGENCIES

CAPITAL EXPENDITURES: Consumers Gas Group estimates capital expenditures,
including new lease commitments, of $123 million for 1999, $123 million for
2000, and $120 million for 2001. These estimates include an attributed portion
of Consumers' anticipated capital expenditures for common plant and equipment.

For further information regarding commitments and contingencies directly
affecting Consumers Gas Group (including those involving former manufactured gas
plant sites), see the Consumers Gas Group Contingencies and Consumers Gas Group
Matters in CMS Energy's Note 2 included and incorporated by reference herein.






                                       10

<PAGE>   11



                               ARTHUR ANDERSEN LLP



                    Report of Independent Public Accountants




To CMS Energy Corporation:

We have reviewed the accompanying balance sheets of CONSUMERS GAS GROUP
(representing a business unit of Consumers Energy Company and its wholly-owned
subsidiary, Michigan Gas Storage Company) as of March 31, 1999 and 1998, and the
related statements of income, common stockholders' equity and cash flows for the
three-month and twelve-month periods then ended. These financial statements are
the responsibility of the Company's management.

We conducted our review in accordance with standards established by the American
Institute of Certified Public Accountants. A review of interim financial
information consists principally of applying analytical procedures to financial
data and making inquiries of persons responsible for financial and accounting
matters. It is substantially less in scope than an audit conducted in accordance
with generally accepted auditing standards, the objective of which is the
expression of an opinion regarding the financial statements taken as a whole.
Accordingly, we do not express such an opinion.

Based on our review, we are not aware of any material modifications that should
be made to the financial statements referred to above for them to be in
conformity with generally accepted accounting principles.

We have previously audited, in accordance with generally accepted auditing
standards, the balance sheet of Consumers Gas Group as of December 31, 1998, and
the related statements of income, common stockholders' equity and cash flows for
the year then ended (not presented herein), and, in our report dated January 26,
1999, we expressed an unqualified opinion on those statements. In our opinion,
the information set forth in the accompanying balance sheet as of December 31,
1998, is fairly stated, in all material respects, in relation to the balance
sheet from which it has been derived.



                                                        /s/ Arthur Andersen LLP

Detroit, Michigan,
  May 11, 1999.

                                       11