<PAGE>

                                    FORM 10-Q


                       SECURITIES AND EXCHANGE COMMISSION

                             Washington, D.C. 20549


    [ X ]         QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF
                              THE SECURITIES EXCHANGE ACT OF 1934

                  For the quarterly period ended June 30, 1998

                                       OR

    [   ]         TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF
                              THE SECURITIES EXCHANGE ACT OF 1934

      For the transition period from _________________ to ________________

                       Commission File number 33-15998-06


                          SWIFT ENERGY MANAGED PENSION

                         ASSETS PARTNERSHIP 1989-C, LTD.
             (Exact name of registrant as specified in its charter)

<TABLE>
<S>                                           <C>       
                  Texas                                   76-0281859
(State or other jurisdiction of organization) (I.R.S. Employer Identification No.)
</TABLE>


                        16825 Northchase Drive, Suite 400
                              Houston, Texas 77060
                    (Address of principal executive offices)
                                   (Zip Code)

                                  (281)874-2700
              (Registrant's telephone number, including area code)

                                      None
              (Former name, former address and former fiscal year,
                          if changed since last report)


Indicate by check mark whether the Registrant (1) has filed all reports required
to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during
the  preceding 12 months (or for such  shorter  period that the  Registrant  was
required  to file  such  reports),  and  (2) has  been  subject  to such  filing
requirements for the past 90 days.

                                 Yes  X    No
                                     ---



<PAGE>


                          SWIFT ENERGY MANAGED PENSION
                         ASSETS PARTNERSHIP 1989-C, LTD.

                                      INDEX



<TABLE>
<CAPTION>
PART I.    FINANCIAL INFORMATION                                                    PAGE
      <S>                                                                            <C>
      ITEM 1.    Financial Statements

            Balance Sheets

                - June 30, 1998 and December 31, 1997                                 3

            Statements of Operations

                - Three month and six month periods ended June 30, 1998 and 1997      4

            Statements of Cash Flows

                - Six month periods ended June 30, 1998 and 1997                      5

            Notes to Financial Statements                                             6

      ITEM 2.    Management's Discussion and Analysis of Financial
                     Condition and Results of Operations                              9

PART II.    OTHER INFORMATION                                                        11


SIGNATURES                                                                           12
</TABLE>



<PAGE>


                          SWIFT ENERGY MANAGED PENSION
                         ASSETS PARTNERSHIP 1989-C, LTD.
                                 BALANCE SHEETS



<TABLE>
<CAPTION>
                                                                                          June 30,           December 31,
                                                                                            1998                 1997
                                                                                       ---------------     ----------------
                                                                                        (Unaudited)
         <S>                                                                           <C>                  <C>           
         ASSETS:

         Current Assets:
              Cash and cash equivalents                                                $      175,422       $      237,208
              Nonoperating interests income receivable                                         47,727               84,237
                                                                                       ---------------     ----------------
                  Total Current Assets                                                        223,149              321,445
                                                                                       ---------------     ----------------
         Nonoperating interests in oil and gas
              properties, using full cost accounting                                        2,303,899            2,294,212
         Less-Accumulated amortization                                                     (2,000,729)          (1,973,105)
                                                                                       ---------------     ----------------
                                                                                              303,170              321,107
                                                                                       ---------------     ----------------
                                                                                       $      526,319       $      642,552
                                                                                       ===============     ================


         LIABILITIES AND PARTNERS' CAPITAL:

         Current Liabilities:
              Accounts Payable                                                         $        3,951       $        4,476
                                                                                       ---------------     ----------------

         Limited Partners' Capital (27,353 Limited Partnership Units;
                                   $100 per unit)                                             522,207              638,059
         General Partners' Capital                                                                161                   17
                                                                                       ---------------     ----------------
                  Total Partners' Capital                                                     522,368              638,076
                                                                                       ---------------     ----------------
                                                                                       $      526,319       $      642,552
                                                                                       ===============     ================
</TABLE>


                 See accompanying notes to financial statements.

                                        3


<PAGE>

                          SWIFT ENERGY MANAGED PENSION
                         ASSETS PARTNERSHIP 1989-C, LTD.
                            STATEMENTS OF OPERATIONS
                                   (Unaudited)





<TABLE>
<CAPTION>
                                                     Three Months Ended                  Six Months Ended
                                                          June 30,                           June 30,
                                              ---------------------------------  ---------------------------------
                                                   1998              1997             1998              1997
                                              ---------------   ---------------  ---------------   ---------------
<S>                                           <C>               <C>              <C>               <C>            
REVENUES:
   Income from nonoperating interests         $        23,845   $        35,270  $        51,317   $       111,387
   Interest income                                      2,516             4,053            5,425             6,000
                                              ---------------   ---------------  ---------------   ---------------
                                                       26,361            39,323           56,742           117,387
                                              ---------------   ---------------  ---------------   ---------------

COSTS AND EXPENSES:
   Amortization                                        12,471            14,363           27,624            32,873
   General and administrative                          11,852            13,736           22,956            28,841
                                              ---------------   ---------------  ---------------   ---------------
                                                       24,323            28,099           50,580            61,714
                                              ---------------   ---------------  ---------------   ---------------
NET INCOME (LOSS)                             $         2,038   $        11,224  $         6,162   $        55,673
                                              ===============   ===============  ===============   ===============



Limited Partners' net income (loss)
   per unit                                   $           .07   $           .41  $           .23   $          2.04
                                              ===============   ===============  ===============   ===============
</TABLE>


                 See accompanying notes to financial statements.

                                        4


<PAGE>


                          SWIFT ENERGY MANAGED PENSION
                         ASSETS PARTNERSHIP 1989-C, LTD.
                            STATEMENTS OF CASH FLOWS
                                   (Unaudited)

<TABLE>
<CAPTION>
                                                                                           Six Months Ended
                                                                                               June 30,
                                                                               ---------------------------------------
                                                                                     1998                    1997
                                                                               ---------------          ---------------
<S>                                                                             <C>                     <C>            
CASH FLOWS FROM OPERATING ACTIVITIES:
    Income (loss)                                                               $        6,162          $        55,673
    Adjustments to reconcile income (loss) to
      net cash provided by operations:
      Amortization                                                                      27,624                   32,873
      Change in assets and liabilities:
        (Increase) decrease in nonoperating interests income receivable                 36,510                   34,589
        (Increase) decrease in other current assets                                         --                  210,729
        Increase (decrease) in accounts payable                                           (525)                   1,254
                                                                               ---------------          ---------------
      Net cash provided by (used in) operating activities                               69,771                  335,118
                                                                               ---------------          ---------------
CASH FLOWS FROM INVESTING ACTIVITIES:
    Additions to nonoperating interests in oil and gas properties                       (9,687)                  (9,969)
                                                                               ---------------          ---------------
CASH FLOWS FROM FINANCING ACTIVITIES:
    Cash distributions to partners                                                    (121,870)                (187,190)
                                                                               ---------------          ---------------
NET INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS                                   (61,786)                 137,959
                                                                               ---------------          ---------------
CASH AND CASH EQUIVALENTS AT BEGINNING OF PERIOD                                       237,208                  166,985
                                                                               ---------------          ---------------
CASH AND CASH EQUIVALENTS AT END OF PERIOD                                      $      175,422          $       304,944
                                                                               ===============          ===============
</TABLE>


                 See accompanying notes to financial statements.

                                        5


<PAGE>

                          SWIFT ENERGY MANAGED PENSION
                         ASSETS PARTNERSHIP 1989-C, LTD.
                          NOTES TO FINANCIAL STATEMENTS
                                   (UNAUDITED)


(1)  General Information -

                  The financial statements included herein have been prepared by
        the  Partnership  and are  unaudited  except  for the  balance  sheet at
        December  31,  1997  which has been  taken  from the  audited  financial
        statements at that date. The financial  statements reflect  adjustments,
        all of which  were of a  normal  recurring  nature,  which  are,  in the
        opinion  of  the  managing   general   partner   necessary  for  a  fair
        presentation.  Certain  information  and footnote  disclosures  normally
        included in financial  statements  prepared in accordance with generally
        accepted  accounting  principles have been omitted pursuant to the rules
        and regulations of the Securities and Exchange Commission  ("SEC").  The
        Partnership  believes adequate disclosure is provided by the information
        presented.  The financial  statements should be read in conjunction with
        the audited  financial  statements  and the notes included in the latest
        Form 10-K.

(2)  Organization and Terms of Partnership Agreement -

                  Swift Energy Managed Pension Assets Partnership 1989-C,  Ltd.,
        a Texas limited partnership ("the Partnership"), was formed on September
        30,  1989,  for  the  purpose  of  purchasing  net  profits   interests,
        overriding  royalty  interests  and  royalty  interests   (collectively,
        "nonoperating interests") in producing oil and gas properties within the
        continental  United  States.  Swift Energy  Company  ("Swift"),  a Texas
        corporation,  and VJM  Corporation  ("VJM"),  a California  corporation,
        serve as Managing  General  Partner and Special  General  Partner of the
        Partnership,   respectively.   The  general  partners  are  required  to
        contribute up to 1/99th of limited  partner net  contributions.  The 322
        limited partners made total capital contributions of $2,735,300.

                  Nonoperating  interests  acquisition  costs and the management
        fee are borne 99 percent by the limited  partners and one percent by the
        general  partners.  Organization and syndication costs were borne solely
        by the limited partners.

                  Generally,  all continuing costs (including development costs,
        operating costs,  general and  administrative  reimbursements and direct
        expenses) and revenues are allocated 90 percent to the limited  partners
        and ten percent to the general partners. If prior to partnership payout,
        however,  the cash  distribution  rate for a  certain  period  equals or
        exceeds  17.5  percent,  then for the  following  calendar  year,  these
        continuing  costs and  revenues  will be  allocated  85  percent  to the
        limited  partners  and  15  percent  to  the  general  partners.   After
        partnership  payout,  continuing  costs and  revenues  will be shared 85
        percent by the limited partners, and 15 percent by the general partners,
        even if the cash  distribution  rate is less than 17.5  percent.  During
        1992 and 1991, the cash distribution rate (as defined in the Partnership
        Agreement)  exceeded  17.5  percent  and  thus,  in 1993 and  1992,  the
        continuing  costs and  revenues  were  shared 85 percent by the  limited
        partners  and 15 percent by the general  partners.  During  1997,  1996,
        1995, 1994 and 1993, the cash  distribution rate fell below 17.5 percent
        and thus, in 1998,  1997,  1996, 1995 and 1994, the continuing costs and
        revenues will be (were) shared 90 percent by the limited partners and 10
        percent by the general partners.

(3)  Significant Accounting Policies -

       Use of Estimates --

                  The  preparation  of financial  statements in conformity  with
        generally accepted  accounting  principles  requires  management to make
        estimates and assumptions that affect the reported amounts of assets and
        liabilities  at the date of the  financial  statements  and the reported
        amounts of revenues and expenses  during the  reporting  period.  Actual
        results could differ from estimates. Certain reclassifications have been
        made to prior year amounts to conform to the current year presentation.

                                       6

<PAGE>


                          SWIFT ENERGY MANAGED PENSION
                         ASSETS PARTNERSHIP 1989-C, LTD.
                    NOTES TO FINANCIAL STATEMENTS (CONTINUED)
                                   (UNAUDITED)


     Nonoperating Interests in Oil and Gas Properties --

                  The Partnership accounts for its ownership interest in oil and
        gas properties using the proportionate consolidation method, whereby the
        Partnership's  share of assets,  liabilities,  revenues  and expenses is
        included in the appropriate classification in the financial statement.

                  For financial  reporting purposes the Partnership  follows the
        "full-cost"  method of accounting for nonoperating  interests in oil and
        gas property costs. Under this method of accounting,  all costs incurred
        in the acquisition of  nonoperating  interests in oil and gas properties
        are capitalized.  The unamortized cost of nonoperating  interests in oil
        and gas  properties is limited to the "ceiling  limitation"  (calculated
        separately for the Partnership,  limited partners and general partners).
        The  "ceiling  limitation"  is  calculated  on  a  quarterly  basis  and
        represents the estimated future net revenues from nonoperating interests
        in proved  properties  using current  prices  discounted at ten percent.
        Proceeds from the sale or disposition of  nonoperating  interests in oil
        and  gas  properties  are  treated  as a  reduction  of the  cost of the
        nonoperating  interests  with no gains or  losses  recognized  except in
        significant transactions.

                  The Partnership computes the provision for amortization of oil
        and gas properties on the units-of-production method. Under this method,
        the provision is calculated by multiplying the total unamortized cost of
        oil and gas  properties  by an overall rate  determined  by dividing the
        physical  units of oil and gas  produced  during the period by the total
        estimated proved oil and gas reserves at the beginning of the period.

                  The calculation of the "ceiling  limitation" and the provision
        for  depreciation,  depletion and  amortization is based on estimates of
        proved reserves. There are numerous uncertainties inherent in estimating
        quantities  of proved  reserves  and in  projecting  the future rates of
        production,  timing and plan of development. The accuracy of any reserve
        estimate  is a  function  of  the  quality  of  available  data  and  of
        engineering  and  geological  interpretation  and  judgment.  Results of
        drilling,  testing and production subsequent to the date of the estimate
        may justify revision of such estimate.  Accordingly,  reserve  estimates
        are  often  different  from  the  quantities  of oil  and gas  that  are
        ultimately recovered.

(4)  Related-Party Transactions -

                  An  affiliate  of  the  Special  General  Partner,  as  Dealer
        Manager,  received  $68,383 for managing and  overseeing the offering of
        the limited  partnership units. A one-time management fee of $68,383 was
        paid to Swift for services performed for the Partnership.

                  The  Partnership  entered  into a Net Profits  and  Overriding
        Royalty Interests Agreement ("NP/OR Agreement") with Swift Energy Income
        Partners 1989-C, Ltd. ("Operating  Partnership"),  managed by Swift, for
        the purpose of acquiring nonoperating interests in producing oil and gas
        properties.   Under  terms  of  the  NP/OR   Agreement,   the  Operating
        Partnership will convey to the Partnership nonoperating interests in the
        aggregate net profits (i.e., oil and gas sales net of related  operating
        costs) of the properties  acquired equal to its  proportionate  share of
        the property acquisition costs.

(5)  Vulnerability Due to Certain Concentrations -

                  The  Partnership's  revenues are primarily the result of sales
        of its oil and natural gas production.  Market prices of oil and natural
        gas may fluctuate and adversely affect operating results.


                                       7

<PAGE>


                          SWIFT ENERGY MANAGED PENSION
                         ASSETS PARTNERSHIP 1989-C, LTD.
                    NOTES TO FINANCIAL STATEMENTS (CONTINUED)
                                   (UNAUDITED)


                  In the normal  course of  business,  the  Partnership  extends
        credit,  primarily in the form of monthly oil and gas sales receivables,
        to various  companies  in the oil and gas  industry  which  results in a
        concentration  of credit risk. This  concentration of credit risk may be
        affected by changes in economic or other  conditions and may accordingly
        impact the  Partnership's  overall  credit risk.  However,  the Managing
        General  Partner  believes  that  the  risk is  mitigated  by the  size,
        reputation, and nature of the companies to which the Partnership extends
        credit.  In  addition,   the  Partnership  generally  does  not  require
        collateral or other security to support customer receivables.

(6)  Fair Value of Financial Instruments -

                  The Partnership's  financial  instruments  consist of cash and
        cash equivalents and short-term  receivables and payables.  The carrying
        amounts  approximate  fair value due to the highly  liquid nature of the
        short-term instruments.

                                       8

<PAGE>

                          SWIFT ENERGY MANAGED PENSION
                         ASSETS PARTNERSHIP 1989-C, LTD.
                MANAGEMENT'S DISCUSSION AND ANALYSIS OF FINANCIAL
                       CONDITION AND RESULTS OF OPERATIONS


GENERAL

      The  Partnership  is formed for the purpose of investing  in  nonoperating
interests in producing oil and gas  properties  located  within the  continental
United States.  In order to accomplish  this, the  Partnership  goes through two
distinct yet  overlapping  phases with respect to its  liquidity  and results of
operations.  When the  Partnership  is formed,  it commences  its  "acquisition"
phase,  with all funds placed in short-term  investments  until required for the
acquisition of nonoperating interests.  Therefore,  the interest earned on these
pre-acquisition  investments  becomes the  primary  cash flow source for initial
partner  distributions.  As the Partnership acquires  nonoperating  interests in
producing properties,  net cash from ownership of nonoperating interests becomes
available  for  distribution,  along  with  the  investment  income.  After  all
partnership funds have been expended on nonoperating  interests in producing oil
and gas properties,  the Partnership enters its "operations"  phase. During this
phase,  income  from  nonoperating  interests  in oil  and gas  sales  generates
substantially all revenues, and distributions to partners reflect those revenues
less all  associated  partnership  expenses.  The  Partnership  may also  derive
proceeds  from  the  sale of  nonoperating  interests  in  acquired  oil and gas
properties,  when the sale of such  interests  is  economically  appropriate  or
preferable to continued operations.

LIQUIDITY AND CAPITAL RESOURCES

      Oil and gas reserves are depleting  assets and therefore often  experience
significant  production  declines each year from the date of acquisition through
the end of the life of the  property.  The primary  source of  liquidity  to the
Partnership comes almost entirely from the income generated from the sale of oil
and gas produced from ownership  interests in oil and gas  properties.  Net cash
provided by operating activities totaled $69,771 and $335,118 for the six months
ended June 30, 1998 and 1997,  respectively.  This source of  liquidity  and the
related results of operations,  and in turn cash distributions,  will decline in
future periods as the oil and gas produced from these  properties  also declines
while production and general and  administrative  costs remain relatively stable
making it unlikely that the Partnership  will hold the properties until they are
fully  depleted,  but will likely  liquidate when a substantial  majority of the
reserves have been produced.  The  Partnership has expended all of the partners'
net commitments available for property acquisitions and development by acquiring
producing oil and gas properties.  The partnership  invests  primarily in proved
producing  properties  with nominal  levels of future costs of  development  for
proven but undeveloped reserves. Significant purchases of additional reserves or
extensive  drilling  activity are not anticipated.  Cash  distributions  totaled
$121,870  and  $187,190  for the six  months  ended  June  30,  1998  and  1997,
respectively.

      Under the NP/OR Agreement, the Managing General Partner acquires interests
in oil and gas properties  from outside  parties and sells these interests to an
affiliated  operating  partnership,  who  in  turn  creates  and  sells  to  the
Partnership  nonoperating  interests in these same oil and gas  properties.  The
Managing  General Partner expects funds available from net profits  interests to
be distributed to the partners.

RESULTS OF OPERATIONS

      The  following  analysis  explains  changes  in the  revenue  and  expense
categories  for the quarter ended June 30, 1998 (current  quarter) when compared
to the quarter  ended June 30,  1997  (corresponding  quarter),  and for the six
months ended June 30, 1998  (current  period),  when  compared to the six months
ended June 30, 1997 (corresponding period).

Three Months Ended June 30, 1998 and 1997

      Income  from  nonoperating  interests  decreased  32 percent in the second
quarter of 1998 when  compared  to the same  quarter in 1997.  Oil and gas sales
declined  $27,786 or 47 percent in the second  quarter of 1998 when  compared to
the  corresponding  quarter in 1997,  primarily  due to  decreased  oil  prices.
Current quarter oil prices declined 44 percent or $7.09/BBL. The decrease in oil
prices had a significant impact on partnership performance. Also, oil production
decreased  53  percent  and  gas   production   declined  14  percent,   further
contributing to decreased  revenues.  Declines in revenues were partially offset
by an increase in gas prices of 43 percent or $.59/MCF  when  compared to second
quarter 1997 prices.

                                       9

<PAGE>

                          SWIFT ENERGY MANAGED PENSION
                         ASSETS PARTNERSHIP 1989-C, LTD.
                MANAGEMENT'S DISCUSSION AND ANALYSIS OF FINANCIAL
                 CONDITION AND RESULTS OF OPERATIONS (CONTINUED)


      Associated  amortization  expense  decreased  13 percent or $1,892 in 1998
compared to second  quarter  1997,  also  related to the  decline in  production
volumes.

Six Months Ended June 30, 1998 and 1997

      Income from nonoperating  interests  decreased 54 percent in the first six
months  of 1998 when  compared  to the same  period  in 1997.  Oil and gas sales
declined  $87,391 or 53 percent in the first six months of 1998 when compared to
the corresponding period in 1997, primarily due to decreased oil and gas prices.
A decline  in oil  prices of 36  percent  or  $6.63/BBL  and in gas prices of 19
percent or $.43/MCF, had a significant impact on partnership performance.  Also,
current  period  oil and gas  production  declined  40 percent  and 29  percent,
respectively,  when compared to the same period in 1997, further contributing to
decreased  revenues.  Sale of the  Gladewater  gas unit in Gregg  County,  Texas
(Cairn Acquisition) had an impact on 1998 partnership production volumes.

      Associated  amortization  expense  decreased  16 percent or $5,249 in 1998
compared  to the first six  months  of 1997,  also  related  to the  decline  in
production volumes.

      During 1998,  partnership  revenues  and costs will be shared  between the
limited partners and general partners in a 90:10 ratio.


                                       10


<PAGE>


                          SWIFT ENERGY MANAGED PENSION
                         ASSETS PARTNERSHIP 1989-C, LTD
                           PART II - OTHER INFORMATION




ITEM 5.    OTHER INFORMATION


                                     -NONE-




                                       11

<PAGE>



                                   SIGNATURES



Pursuant to the  requirements of Section 13 or 15(d) of the Securities  Exchange
Act of 1934,  the  Registrant  has duly  caused  this report to be signed on its
behalf by the undersigned thereunto duly authorized.


                                        SWIFT ENERGY MANAGED PENSION
                                        ASSETS PARTNERSHIP 1989-C, LTD.
                                        (Registrant)

                             By:        SWIFT ENERGY COMPANY
                                        Managing General Partner

Date:     August 4, 1998     By:        /s/ John R. Alden
          --------------                ---------------------------------
                                        John R. Alden
                                        Senior Vice President, Secretary
                                        and Principal Financial Officer

Date:     August 4, 1998     By:        /s/ Alton D. Heckaman, Jr.
          --------------                ---------------------------------
                                        Alton D. Heckaman, Jr.
                                        Vice President, Controller
                                        and Principal Accounting Officer


                                       12