<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 March 31, 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

                - March 31, 1998 and December 31, 1997                    3

            Statements of Operations

                - Three month periods ended March 31, 1998 and 1997       4

            Statements of Cash Flows

                - Three month periods ended March 31, 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                                            10


SIGNATURES                                                               11
</TABLE>


<PAGE>

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



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

         Current Assets:
              Cash and cash equivalents                                                $      213,650       $      237,208
              Nonoperating interests income receivable                                         56,070               84,237
                                                                                       --------------       --------------
                   Total Current Assets                                                       269,720              321,445
                                                                                       --------------       --------------
         Nonoperating interests in oil and gas
              properties, using full cost accounting                                        2,295,393            2,294,212
         Less-Accumulated amortization                                                     (1,988,258)          (1,973,105)
                                                                                       --------------       --------------
                                                                                              307,135              321,107
                                                                                       --------------       --------------
                                                                                       $      576,855       $      642,552
                                                                                       ==============       ==============


         LIABILITIES AND PARTNERS' CAPITAL:

         Current Liabilities:
              Accounts Payable                                                         $        3,701       $        4,476
                                                                                       --------------       --------------

         Limited Partners' Capital (27,353 Limited Partnership Units;
                                    $100 per unit)                                            572,169              638,059
         General Partners' Capital                                                                985                   17
                                                                                       --------------       --------------
                   Total Partners' Capital                                                    573,154              638,076
                                                                                       --------------       --------------
                                                                                       $      576,855       $      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
                                                                                              March 31,
                                                                                 ---------------------------------
                                                                                       1998               1997
                                                                                 ---------------   ---------------
         <S>                                                                     <C>               <C>
         REVENUES:
             Income from nonoperating interests                                  $        27,471   $        76,116
             Interest income                                                               2,909             1,947
                                                                                 ---------------   ---------------
                                                                                          30,380            78,063
                                                                                 ---------------   ---------------
         COSTS AND EXPENSES:
             Amortization                                                                 15,153            18,510
             General and administrative                                                   11,103            15,104
                                                                                 ---------------   ---------------
                                                                                          26,526            33,614
                                                                                 ---------------   ---------------
         NET INCOME (LOSS)                                                       $         4,124   $        44,449
                                                                                 ===============   ===============
</TABLE>


         Limited Partners' net income (loss)
             per unit

         March 31, 1998                       $           .15
                                              ===============
         March 31, 1997                       $          1.63
                                              ===============


                 See accompanying notes to financial statements.

                                        4


<PAGE>

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


<TABLE>
<CAPTION>
                                                                                          Three Months Ended
                                                                                               March 31,
                                                                                --------------------------------------
                                                                                       1998                    1997
                                                                                ----------------        --------------
<S>                                                                             <C>                     <C>
CASH FLOWS FROM OPERATING ACTIVITIES:
    Income (Loss)                                                               $          4,124        $        44,449
    Adjustments to reconcile income (loss) to
      net cash provided by operations:
      Amortization                                                                        15,153                 18,510
      Change in assets and liabilities:
        (Increase) decrease in nonoperating interests income receivable                   28,167                219,525
        Increase (decrease) in accounts payable                                             (775)                 1,710
                                                                                ----------------        ---------------
               Net cash provided by (used in) operating activities                        46,669                284,194
                                                                                ----------------        ---------------
CASH FLOWS FROM INVESTING ACTIVITIES:
        Additions to nonoperating interests
           in oil and gas properties                                                      (1,181)               (13,043)
                                                                                ----------------        ---------------
CASH FLOWS FROM FINANCING ACTIVITIES:
      Cash distributions to partners                                                     (69,046)               (95,570)
                                                                                ----------------        ---------------
NET INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS                                     (23,558)               175,581
                                                                                ----------------        ---------------
CASH AND CASH EQUIVALENTS AT BEGINNING OF PERIOD                                         237,208                166,985
                                                                                ----------------        ---------------
CASH AND CASH EQUIVALENTS AT END OF PERIOD                                      $        213,650        $       342,566
                                                                                ================        ===============
</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 are being 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 statements.

                  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 Partnership has been
        conveyed a  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.


                                       7


<PAGE>


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


(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.

                  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  $46,669 and
$284,194 for the three months ended March 31, 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
the  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   partner's  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 $69,046 and $95,570 for the three months
ended March 31, 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.

RESULTS OF OPERATIONS

         Income from  nonoperating  interests  decreased 64 percent in the first
quarter of 1998 when  compared  to the same  quarter in 1997.  Oil and gas sales
declined $59,605 or 57 percent in the first quarter of 1998 when compared to the
corresponding  quarter in 1997, primarily due to decreased gas and oil prices. A
decline in gas prices of 42 percent or $1.22/MCF and in oil prices of 34 percent
or $6.97/BBL had a significant impact on partnership performance.  Also, current
quarter gas and oil production declined 41 percent and 30 percent,  respectively
when compared to first quarter 1997 production volumes,  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.

         Total  amortization  expense  decreased  18  percent  or $3,357 in 1998
compared  to first  quarter  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 an 90:10 ratio.


                                       9


<PAGE>

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




ITEM 5.    OTHER INFORMATION


                                     -NONE-




                                       10


<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:     May 5, 1998             By:        /s/ John R. Alden
          -----------                        ----------------------------------
                                             John R. Alden
                                             Senior Vice President, Secretary
                                             and Principal Financial Officer

Date:     May 5, 1998             By:        /s/ Alton D. Heckaman, Jr.
          -----------                        ----------------------------------
                                             Alton D. Heckaman, Jr.
                                             Vice President, Controller
                                             and Principal Accounting Officer


                                       11