BGE STOCK OPTION AGREEMENT

                  This STOCK OPTION  AGREEMENT,  dated as of September 22, 1995,
(the  "Agreement")  by  and  between  Baltimore  Gas  and  Electric  Company,  a
corporation  formed under the laws of the State of Maryland  ("BGE") and Potomac
Electric Power Company,  a corporation  formed under the laws of the District of
Columbia and the Commonwealth of Virginia ("PEPCO"),


                          W I T N E S S E T H T H A T:


                  WHEREAS,  concurrently with the execution and delivery of this
Agreement,  BGE, PEPCO and RH Acquisition  Corp., a corporation formed under the
laws of the State of Maryland  (the  "Company"),  are entering into an Agreement
and Plan of Merger,  dated as of September 22, 1995,  (the "Merger  Agreement"),
which  provides,  inter  alia,  upon the terms  and  subject  to the  conditions
thereof,  for the  merger  of BGE and  PEPCO  with  and into  the  Company  (the
"Merger");

                  WHEREAS,  in  connection  with  the  execution  of the  Merger
Agreement,  BGE and PEPCO are entering  into a certain  stock  option  agreement
dated as of the date hereof  whereby  PEPCO grants to BGE an option with respect
to  certain  shares of  PEPCO's  common  stock on the terms and  subject  to the
conditions set forth therein (the "PEPCO Stock Option Agreement"); and

                  WHEREAS,  as a condition to PEPCO's  willingness to enter into
the Merger Agreement, PEPCO has requested that BGE agree, and BGE has so agreed,
to grant to PEPCO an option  with  respect  to  certain  shares of BGE's  common
stock, on the terms and subject to the conditions set forth herein;

                  NOW,  THEREFORE,  to  induce  PEPCO to enter  into the  Merger
Agreement  and the PEPCO Stock Option  Agreement,  and in  consideration  of the
representations,  warranties,  covenants and agreements contained herein, in the
Merger  Agreement and in the PEPCO Stock Option  Agreement,  the parties hereto,
intending to be legally bound, hereby agree as follows:

                  1.       GRANT OF OPTION.

                  (a) BGE hereby  grants PEPCO an  irrevocable  option (the "BGE
Option") to purchase up to 29,357,896 shares,  subject to adjustment as provided
in Section 11 (the "BGE  Shares"),  of common stock,  without par value,  of BGE
(the "BGE  Common  Stock")  (being  19.9% of the  number of shares of BGE Common
Stock outstanding as of August 31, 1995) in the manner set forth below,







at a price (the  "Exercise  Price") per BGE Share of $25.925  (which is equal to
the Fair Market Value (as defined below) of a BGE Share as of the date hereof).

                  (b) The Exercise Price shall be payable, at PEPCO's option, as
follows:

                           (i)  in cash, or

                           (ii) subject to BGE's having  obtained the  approvals
         of any  Governmental  Authority  required  for BGE to acquire the PEPCO
         Shares (as defined below) from PEPCO, in shares of common stock,  $1.00
         par value, of PEPCO ("PEPCO Shares"),

in either case in accordance with Section 4 hereof.

                  (c)  Notwithstanding  the  foregoing,  in no event  shall  the
number of BGE Shares for which the BGE Option is exercisable exceed 19.9% of the
number of issued and outstanding shares of BGE Common Stock.

                  (d) As used herein, the "Fair Market Value" of any share shall
be the average of the daily  closing  sales price for such share on the New York
Stock  Exchange (the "NYSE") during the ten NYSE trading days prior to the fifth
NYSE trading day preceding the date such Fair Market Value is to be determined.

                  (e) Capitalized terms used herein but not defined herein shall
have the meanings set forth in the Merger Agreement.

                  2.  EXERCISE OF OPTION.

                  (a) The BGE Option may be exercised  by PEPCO,  in whole or in
part,  at any time or from  time to time  after  the  Merger  Agreement  becomes
terminable by PEPCO under  circumstances  which could entitle PEPCO to a payment
under Section 9.3(b) of the Merger  Agreement,  regardless of whether the Merger
Agreement  is  actually  terminated  or  whether  there  occurs a closing of any
Business  Combination  involving  a Target  Party or a closing by which a Target
Party becomes a subsidiary (any such event by which the Merger Agreement becomes
so terminable by PEPCO being referred to herein as a "Trigger Event").

                  (b)  (i) BGE shall  notify PEPCO  promptly  in  writing of the
         occurrence of any Trigger Event, it being understood that the giving of
         such  notice by BGE shall not be a  condition  to the right of PEPCO to
         exercise the BGE Option.

                       (ii)  In the  event  PEPCO  wishes  to  exercise  the BGE
         Option,  PEPCO  shall  deliver  to BGE  written  notice  (an  "Exercise
         Notice")  specifying  the  total  number  of BGE  Shares  it  wishes to
         purchase.



                                      -2-





                       (iii)  Upon the  giving  by PEPCO to BGE of the  Exercise
         Notice  and the  tender of the  applicable  aggregate  Exercise  Price,
         PEPCO,  to  the  extent  permitted  by  law  and  BGE's  organizational
         documents,  and provided  that the  conditions  to BGE's  obligation to
         issue the BGE  Shares to River  hereunder  set forth in  Section 3 have
         been satisfied or waived, shall be deemed to be the holder of record of
         the BGE Shares  issuable upon such exercise,  notwithstanding  that the
         stock transfer  books of BGE shall then be closed or that  certificates
         representing  such BGE Shares  shall not then be actually  delivered to
         PEPCO.

                       (iv)  Each  closing  of  a  purchase  of  BGE  Shares  (a
         "Closing")  shall occur at a place, on a date, and at a time designated
         by PEPCO in an Exercise  Notice  delivered at least two  business  days
         prior to the date of the Closing.

                  (c) The BGE Option shall  terminate upon the earliest to occur
of:

                       (i) the Effective Time of the Merger;

                       (ii) the termination of the Merger Agreement  pursuant to
         Section 9.1 thereof other than under  circumstances which could entitle
         PEPCO to a payment under Section 9.3(b) of the Merger Agreement; and

                       (iii) 180 days  following any  termination  of the Merger
         Agreement upon or during the  continuance of a Trigger Event (or if, at
         the  expiration  of such  180 day  period,  the BGE  Option  cannot  be
         exercised by reason of any applicable judgment,  decree,  order, law or
         regulation,  ten business days after such  impediment to exercise shall
         have been removed or shall have become final and not subject to appeal,
         but in no event under this clause (iii) later than March 31, 1998).

                  (d) Notwithstanding  the foregoing,  the BGE Option may not be
exercised  if PEPCO  is in  material  breach  of any of its  representations  or
warranties,  or in  material  breach  of  any of its  covenants  or  agreements,
contained in this Agreement or in the Merger Agreement.

                  3.  CONDITIONS TO CLOSING.  The obligation of BGE to issue the
BGE Shares to PEPCO hereunder is subject to the conditions that

                  (a) all waiting periods,  if any, under the HSR Act applicable
to the  issuance  of the BGE Shares  hereunder  shall have  expired or have been
terminated;

                  (b) the BGE Shares,  and any PEPCO  Shares which are issued in
payment of the Exercise Price,  shall have been approved for listing on the NYSE
upon official notice of issuance;


                                      -3-






                  (c) all consents,  approvals,  orders or authorizations of, or
registrations,  declarations  or  filings  with,  any  federal,  state  or local
administrative   agency  or  commission  or  other   federal,   state  or  local
Governmental  Authority, if any, required in connection with the issuance of the
BGE  Shares  hereunder  shall have been  obtained  or made,  including,  without
limitation,  the  approval  of the SEC under  Section  10 of the 1935  Act,  the
approval of the  Maryland  Commission  of the  issuance of the BGE Shares by BGE
and, if applicable,  the acquisition of BGE Shares by PEPCO, and the approval of
the Maryland  Commission of the  acquisition  of the BGE Shares by PEPCO and, if
applicable, the acquisition by BGE of the PEPCO Shares constituting the Exercise
Price hereunder; and

                  (d) no preliminary  or permanent  injunction or other order by
any court of competent  jurisdiction  prohibiting or otherwise  restraining such
issuance shall be in effect.

The condition set forth in paragraph (b) above may be waived by BGE, in the case
of PEPCO Shares, and by PEPCO, in the case of BGE Shares, in the sole discretion
of the waiving party.

                  4.  CLOSING.  At any Closing,

                  (a) BGE  shall  deliver  to  PEPCO  or its  designee  a single
certificate in definitive form  representing the number of BGE Shares designated
by PEPCO in its Exercise  Notice,  such certificate to be registered in the name
of PEPCO and to bear the legend set forth in Section 12; and

                  (b) PEPCO shall deliver to BGE the aggregate price for the BGE
Shares so designated and being purchased by

                           (i)  wire transfer of immediately available funds
         or certified check or bank check, or

                           (ii) subject to the condition in Section 1(b)(ii),  a
         certificate  or  certificates  representing  the number of PEPCO Shares
         being  issued  by  PEPCO  in  consideration   thereof,   determined  in
         accordance with Section 4(c).

                  (c) In the event  that  PEPCO  issues  PEPCO  Shares to BGE in
consideration  of BGE Shares  pursuant  to Section  4(b)(ii),  the number of BGE
Shares to be so issued shall be equal to the quotient obtained by dividing:

                           (i)  the product of (x) the number of BGE Shares
         with respect to which the BGE Option is being exercised and
         (y) the Exercise Price, by

                           (ii) the Fair Market  Value of the PEPCO Shares as of
         the  date  immediately  preceding  the  date  the  Exercise  Notice  is
         delivered to BGE.


                                      -4-






                  (d) BGE shall pay all expenses,  and any and all United States
Federal,  state and  local  taxes,  and other  charges  that may be  payable  in
connection with the preparation,  issue and delivery of stock certificates under
this Section 4.

                  5.  REPRESENTATIONS  AND WARRANTIES OF BGE. BGE represents and
warrants to PEPCO that

                  (a) Subject to any required regulatory approvals,  BGE has the
corporate  power and authority to enter into this Agreement and to carry out its
obligations  hereunder,  subject in the case of the repurchase of the BGE Shares
pursuant to Section 7(a) to applicable  law and the  provisions,  BGE's Restated
Articles of Incorporation, as amended (the "BGE Articles");

                  (b) this  Agreement  has been duly and  validly  executed  and
delivered by BGE, and,  assuming the due  authorization,  execution and delivery
hereof by PEPCO,  constitutes a valid and binding obligation of BGE, enforceable
against BGE in accordance with its terms, except as may be limited by applicable
bankruptcy,  insolvency, fraudulent conveyance,  reorganization or other similar
laws affecting the enforcement of creditors' rights  generally,  and except that
the availability of equitable remedies,  including specific performance,  may be
subject to the discretion of any court before which any proceeding  therefor may
be brought;

                  (c) BGE has taken all necessary  corporate action to authorize
and reserve for  issuance  and to permit it to issue,  upon  exercise of the BGE
Option,  and at all times from the date hereof through the expiration of the BGE
Option will have reserved,  29,357,896  authorized and unissued BGE Shares, such
amount being subject to adjustment as provided in Section 11, all of which, upon
their issuance and delivery in accordance with the terms of this Agreement, will
be validly issued, fully paid and nonassessable;

                  (d) upon delivery of the BGE Shares to PEPCO upon the exercise
of the BGE  Option,  PEPCO will  acquire  the BGE  Shares  free and clear of all
claims,  liens,  charges,  encumbrances  and  security  interests  of any nature
whatsoever;

                  (e)  except as  described  in  Section  5.4(b)  of the  Merger
Agreement,  the execution  and delivery of this  Agreement by BGE does not, and,
subject to compliance  with  applicable law and the BGE Articles with respect to
the repurchase of the BGE Shares  pursuant to Section 7(a), the  consummation by
BGE of the transactions contemplated hereby will not, violate, conflict with, or
result in a breach of any provision of, or constitute a default (with or without
notice or a lapse of time, or both) under,  or result in the  termination of, or
accelerate  the  performance  required by, or result in a right of  termination,
cancellation,  or  acceleration  of any  obligation  or the  loss of a  material
benefit under, or the creation of a lien, pledge,


                                      -5-





security interest or other encumbrance on assets (any such conflict,  violation,
default, right of termination,  cancellation or acceleration,  loss or creation,
hereinafter a "Violation") of BGE or any of its subsidiaries, pursuant to

                           (i) any provision of the BGE Articles or the
         Bylaws of BGE,

                           (ii) any  provisions  of any material  loan or credit
         agreement, note, mortgage,  indenture, lease, BGE benefit plan or other
         agreement,  obligation,   instrument,  permit,  concession,  franchise,
         license  (any of the  foregoing  in  effect  on the date  hereof  being
         referred to as a "Material Contract"), or

                           (iii) any judgment, order, decree, statute, law,
         ordinance, rule or regulation applicable to BGE or its
         properties or assets,

which Violation, in the case of each of clauses (ii) and (iii), could reasonably
be expected to have a BGE Material Adverse Effect (except that no representation
or  warranty is given  concerning  any  Violation  of a Material  Contract  with
respect to the repurchase of BGE Shares pursuant to Section 7(a));

                  (f)  except as  described  in  Section  5.4(c)  of the  Merger
Agreement or Section 3 hereof,  the execution and delivery of this  Agreement by
BGE does not, and the performance of this Agreement by BGE will not, require any
consent,  approval,  authorization  or permit or filing with or notification to,
any Governmental Authority;

                  (g) none of BGE, any of its affiliates or anyone acting on its
or their behalf,  has issued,  sold or offered any security of BGE to any person
under  circumstances  that would cause the issuance  and sale of BGE Shares,  as
contemplated by this Agreement,  to be subject to the registration  requirements
of the  Securities  Act as in  effect  on the date  hereof,  and,  assuming  the
representations  and warranties of PEPCO  contained in Section 6(g) are true and
correct,  the issuance,  sale and delivery of the BGE Shares  hereunder would be
exempt  from  the  registration  and  prospectus  delivery  requirements  of the
Securities  Act,  as in  effect on the date  hereof  (and BGE shall not take any
action  which  would  cause the  issuance,  sale,  and  delivery  of BGE  Shares
hereunder not to be exempt from such requirements); and

                  (h) any PEPCO Shares acquired  pursuant to this Agreement will
be acquired for BGE's own account, for investment purposes only, and will not be
acquired by BGE with a view to the public  distribution  thereof in violation of
any applicable provision of the Securities Act.




                                      -6-





                  6.  REPRESENTATIONS  AND WARRANTIES OF PEPCO. PEPCO represents
and warrants to BGE that

                  (a) PEPCO has the corporate  power and authority to enter into
this Agreement and to carry out its obligations hereunder;

                  (b) this  Agreement  has been duly and  validly  executed  and
delivered by PEPCO and, assuming the due  authorization,  execution and delivery
hereof, constitutes a valid and binding obligation of PEPCO, enforceable against
PEPCO in  accordance  with its terms,  except as may be  limited  by  applicable
bankruptcy, insolvency, fraudulent conveyance,  reorganization, or other similar
laws affecting the enforcement of creditors' rights  generally,  and except that
the availability of equitable remedies,  including specific performance,  may be
subject  to the  discretion  of any court  before  which any  proceeding  may be
brought;

                  (c) prior to any delivery of PEPCO Shares in  consideration of
the purchase of BGE Shares pursuant hereto,  PEPCO will have taken all necessary
corporate  action to authorize for issuance and to permit it to issue such PEPCO
Shares,  all of which,  upon their issuance and delivery in accordance  with the
terms of this Agreement, will be validly issued, fully paid and nonassessable;

                  (d)  upon  any  delivery  of  such  PEPCO  Shares  to  BGE  in
consideration  of the purchase of BGE Shares pursuant  hereto,  BGE will acquire
the PEPCO Shares free and clear of all claims, liens, charges,  encumbrances and
security interests of an nature whatsoever;

                  (e)  except as  described  in  Section  4.4(b)  of the  Merger
Agreement,  the execution and delivery of this  Agreement by PEPCO does not, and
the  consummation  by PEPCO of the  transactions  contemplated  hereby will not,
violate,  conflict  with,  or  result  in the  breach  of any  provision  of, or
constitute a default (with or without notice or a lapse of time, or both) under,
or result in any Violation by PEPCO or any of its subsidiaries, pursuant to

                       (i) any  provision  of the Articles of  Incorporation  or
         Bylaws of PEPCO,

                       (ii)  any  provisions  of any loan or  credit  agreement,
         note,  mortgage,   indenture,   lease,  PEPCO  benefit  plan  or  other
         agreement,  obligation,   instrument,  permit,  concession,  franchise,
         license, or

                       (iii)  any  judgment,   order,  decree,   statute,   law,
         ordinance,  rule or regulation applicable to PEPCO or its properties or
         assets,



                                      -7-





which  Violation,  in the case of each of  clauses  (ii) or (iii),  would have a
PEPCO Material Adverse Effect;

                  (f)  except as  described  in  Section  4.4(c)  of the  Merger
Agreement or Section 3 hereof,  the execution and delivery of this  Agreement by
PEPCO does not, and the consummation by PEPCO of the  transactions  contemplated
hereby will not, require any consent,  approvals  authorization or permit of, or
filing with or notification to, any Governmental Authority; and

                  (g) any BGE Shares  acquired  upon  exercise of the BGE Option
will be acquired for PEPCO's own account,  for investment purposes only and will
not be, and the BGE Option is not  being,  acquired  by PEPCO with a view to the
public  distribution  thereof,  in violation of any applicable  provision of the
Securities Act.

                  7.  CERTAIN REPURCHASES.

                  (a) PEPCO "PUT". At the request of PEPCO by written notice (x)
at any time  during  which the BGE Option is  exercisable  pursuant to Section 2
(the  "Repurchase  Period"),  BGE (or any successor  entity  thereof)  shall, if
permitted by applicable law, the BGE Articles and BGE's Material  Contracts (but
notwithstanding  any  insufficiency  in the number of BGE Shares  authorized for
issuance upon the exercise of the BGE Option),  repurchase from PEPCO all or any
portion of the BGE Option,  at the price set forth in subparagraph (i) below, or
(y) at any time  prior to March 31,  1997  (provided  that  such  date  shall be
extended  to March 31, 1998 under the  circumstances  where the date after which
either party may terminate the Merger  Agreement  pursuant to Section  9.1(b) of
the Merger Agreement has been extended to March 31, 1998), BGE (or any successor
entity  thereof)  shall,  if permitted by  applicable  law, the BGE Articles and
BGE's Material  Contracts,  repurchase  from PEPCO all or any portion of the BGE
Shares purchased by PEPCO pursuant to the BGE Option,  at the price set forth in
subparagraph (ii) below:

                           (i) the difference  between the "Market/Offer  Price"
         (as defined  below) for shares of BGE Common Stock as of the date PEPCO
         gives  notice of its intent to exercise its rights under this Section 7
         and  the  Exercise  Price,  multiplied  by the  number  of  BGE  Shares
         purchasable pursuant to the BGE Option (or portion thereof with respect
         to which PEPCO is exercising its rights under this Section 7), but only
         if the  Market/Offer  Price is greater  than the  Exercise  Price.  For
         purposes of this subparagraph (i),  "Market/Offer Price" shall mean, as
         of any date,  the higher of (x) the price per share  offered as of such
         date  pursuant  to any  tender or  exchange  offer or other  offer with
         respect to a Business  Combination  involving  BGE as the Target Party,
         which was made prior to such date and not terminated or withdrawn as of
         such date and (y) the Fair Market  Value of BGE Common Stock as of such
         date.



                                      -8-





                           (ii) the  product of (x) the sum of (A) the  Exercise
         Price paid by PEPCO per BGE Share acquired  pursuant to the BGE Option,
         and (B) the difference between the "Offer Price" (as defined below) and
         the  Exercise  Price,  but only if the Offer Price is greater  than the
         Exercise  Price,  and (y) the number of BGE Shares so to be repurchased
         pursuant  to this  Section 7. For  purposes of this  clause  (ii),  the
         "Offer Price" shall be the highest price per share offered  pursuant to
         a  tender  or  exchange  offer  or  other  Business  Combination  offer
         involving BGE as the Target Party during the Repurchase Period prior to
         the delivery by PEPCO of a notice of repurchase.

                  (b) REDELIVERY OF PEPCO SHARES. If PEPCO shall have previously
elected to purchase BGE Shares pursuant to the exercise of the BGE Option by the
issuance and delivery of PEPCO Shares, then BGE shall, if so requested by PEPCO,
in  fulfillment  of its  obligation  pursuant to Section  7(a)(y) (that is, with
respect to the Exercise  Price only and without  limitation to its obligation to
pay additional consideration under clause (B) of Section 7(a)(ii)(x)), redeliver
the  certificates  for such PEPCO Shares to PEPCO,  free and clear of all liens,
claims,  charges and  encumbrances of any kind or nature  whatsoever;  provided,
however,  that if at any time less than all of the BGE  Shares so  purchased  by
PEPCO  pursuant  to the BGE  Option are to be  repurchased  by BGE  pursuant  to
Section 7(a)(y),  then (i) BGE shall be obligated to redeliver to PEPCO the same
proportion of such PEPCO  Shares as the  number of BGE  shares  that BGE is then
obligated to repurchase bears to the number of BGE Shares acquired by PEPCO upon
exercise of the BGE Option and (ii) PEPCO  shall  issue to BGE new  certificates
representing  those PEPCO  Shares which are not due to be  redelivered  to PEPCO
pursuant  to this  Section  7(b) to the  extent  that  excess  PEPCO  Shares are
included in the certificates redelivered to PEPCO by BGE.

                  (c) PAYMENT AND  REDELIVERY  OF BGE OPTIONS OR SHARES.  In the
event PEPCO  exercises  its rights under this  Section 7, BGE shall,  within ten
business  days  thereafter,  pay the  required  amount  to PEPCO in  immediately
available  funds  and  PEPCO  shall  surrender  to BGE  the  BGE  Option  or the
certificate  or  certificates  evidencing  the BGE  Shares  purchased  by  PEPCO
pursuant  hereto,  and PEPCO shall  warrant  that it owns the BGE Option or such
shares  and that the BGE  Option or such  shares  are then free and clear of all
liens,  claims,  damages,  charges  and  encumbrances  of  any  kind  or  nature
whatsoever.

                  (d) PEPCO "CALL".  If PEPCO has elected to purchase BGE Shares
pursuant to the exercise of the BGE Option by the issuance and delivery of PEPCO
Shares,  notwithstanding  that  PEPCO may no longer  hold any such BGE Shares or
that PEPCO  elects not to exercise  its other rights under this Section 7, PEPCO
may require,  at any time or from time to time prior to March 31, 1997 (provided
that such date shall be extended to March 31, 1998 under the circumstances where
the date after which either party


                                      -9-





may  terminate  the Merger  Agreement  pursuant to Section  9.1(b) of the Merger
Agreement has been  extended to March 31,  1998),  BGE to sell to PEPCO any such
PEPCO Shares at the price  attributed to such PEPCO Shares pursuant to Section 4
plus  interest  at the rate of 8.75% per annum on such  amount  from the Closing
Date relating to the exchange of such PEPCO Shares  pursuant to Section 4 to the
Closing  Date under this  Section  7(d) less any  dividends on such PEPCO Shares
paid during such period or declared and payable to  stockholders  of record on a
date during such period.

                  (e) REPURCHASE  PRICE REDUCED AT PEPCO'S OPTION.  In the event
the repurchase price specified in Section 7(a) would subject the purchase of the
BGE Option or the BGE Shares  purchased by PEPCO pursuant to the BGE Option to a
vote of the  shareholders of BGE pursuant to applicable law or the BGE Articles,
then PEPCO may, at its election,  reduce the repurchase price to an amount which
would permit such repurchase without the necessity for such a shareholder vote.

                  8.  VOTING OF SHARES.  Following  the date hereof and prior to
the fifth  anniversary of the date hereof (the  "Expiration  Date"),  each party
shall vote any shares of capital stock of the other party acquired by such party
pursuant to this  Agreement  ("Restricted  Shares"),  including any PEPCO Shares
issued  pursuant to Section  1(b), or otherwise  beneficially  owned (within the
meaning of Rule 13d-3 promulgated under the Securities  Exchange Act of 1934, as
amended (the "Exchange  Act")), by such party on each matter submitted to a vote
of  shareholders  of such other  party for and  against  such matter in the same
proportion as the vote of all other  shareholders  of such other party are voted
(whether by proxy or otherwise) for and against such matter.

                  9. RESTRICTIONS ON TRANSFER.

                  (a)  RESTRICTIONS ON TRANSFER.  Prior to the Expiration  Date,
neither party shall,  directly or indirectly,  by operation of law or otherwise,
sell, assign,  pledge, or otherwise dispose of or transfer any Restricted Shares
beneficially  owned by such party, other than (i) pursuant to Section 7, or (ii)
in accordance with Section 9(b) or Section 10.

                  (b) PERMITTED  SALES.  Following the termination of the Merger
Agreement, a party shall be permitted to sell any Restricted Shares beneficially
owned by it if such sale is made pursuant to a tender or exchange offer that has
been approved or recommended,  or otherwise  determined to be fair to and in the
best  interests of the  shareholders  of the other  party,  by a majority of the
members of the Board of  Directors  of such other party,  which  majority  shall
include a majority of directors who were directors prior to the  announcement of
such tender or exchange offer.



                                      -10-





                  10. REGISTRATION RIGHTS.

                  (a) Following the termination of the Merger Agreement,  either
party hereto that owns Restricted Shares (a "Designated  Holder") may by written
notice (the "Registration Notice") to the other party (the "Registrant") request
the  Registrant  to  register  under the  Securities  Act all or any part of the
Restricted Shares beneficially owned by such Designated Holder (the "Registrable
Securities")  pursuant  to a  bona  fide  firm  commitment  underwritten  public
offering,  in which the Designated  Holder and the underwriters  shall effect as
wide a distribution of such Registrable  Securities as is reasonably practicable
and shall use their best efforts to prevent any person  (including any Group (as
used in Rule 13d-5 under the Exchange Act)) and its affiliates  from  purchasing
through  such  offering  Restricted  Shares  representing  more  than  1% of the
outstanding shares of common stock of the Registrant on a fully diluted basis (a
"Permitted Offering").

                  (b)  The  Registration  Notice  shall  include  a  certificate
executed by the Designated Holder and its proposed managing  underwriter,  which
underwriter  shall  be an  investment  banking  firm  of  nationally  recognized
standing (the "Manager"), stating that

                           (i) they have a good faith intention to commence
         promptly a Permitted Offering, and

                           (ii) the Manager in good faith believes  that,  based
         on the then-prevailing  market conditions,  it will be able to sell the
         Registrable  Securities  at a per share  price equal to at least 80% of
         the then Fair Market Value of such shares.

                  (c)  The  Registrant  (and/or  any  person  designated  by the
Registrant)  shall  thereupon  have the option  exercisable  by  written  notice
delivered to the Designated Holder within ten business days after the receipt of
the Registration Notice, irrevocably to agree to purchase all or any part of the
Registrable  Securities  proposed to be so sold for cash at a price (the "Option
Price") equal to the product of (i) the number of  Registrable  Securities to be
so  purchased  by the  Registrant  and (ii) the then Fair  Market  Value of such
shares.

                  (d) Any purchase of  Registrable  Securities by the Registrant
(or its  designee)  under Section 10(c) shall take place at a closing to be held
at the principal  executive  offices of the  Registrant or at the offices of its
counsel at any reasonable date and time designated by the Registrant and/or such
designee in such  notice  within  twenty  business  days after  delivery of such
notice,  and any  payment  for the  shares to be so  purchased  shall be made by
delivery at the time of such closing in immediately available funds.



                                      -11-





                  (e) If the  Registrant  does not elect to exercise  its option
pursuant to this Section 10 with respect to all Registrable Securities, it shall
use its best efforts to effect,  as promptly as  practicable,  the  registration
under the Securities Act of the unpurchased  Registrable  Securities proposed to
be so sold; provided, however, that

                           (i) neither party shall be entitled to more than
         an aggregate of two effective registration statements
         hereunder, and

                           (ii) the Registrant  will not be required to file any
         such registration statement during any period of time (not to exceed 40
         days after  such  request in the case of clause (A) below or 90 days in
         the case of clauses (B) and (C) below) when

                  (A) the  Registrant is in  possession  of material  non-public
information which it reasonably believes would be detrimental to be disclosed at
such time and, in the  opinion of counsel to the  Registrant,  such  information
would have to be disclosed if a registration statement were filed at that time;

                  (B) the  Registrant is required  under the  Securities  Act to
include  audited  financial  statements  for any  period  in  such  registration
statement and such  financial  statements are not yet available for inclusion in
such registration statement; or

                  (C) the Registrant  determines,  in its  reasonable  judgment,
that such registration would interfere with any financing,  acquisition or other
material transaction involving the Registrant or any of its affiliates.

                    (f) The Registrant  shall use its reasonable best efforts to
cause any Registrable  Securities  registered  pursuant to this Section 10 to be
qualified for sale under the  securities or Blue Sky laws of such  jurisdictions
as the  Designated  Holder  may  reasonably  request  and  shall  continue  such
registration or qualification in effect in such jurisdiction; provided, however,
that the  Registrant  shall not be  required  to qualify to do  business  in, or
consent to general  service of process  in, any  jurisdiction  by reason of this
provision.

                  (g) The  registration  rights set forth in this Section 10 are
subject to the condition that the Designated Holder shall provide the Registrant
with such information with respect to such holder's Registrable Securities,  the
plans for the distribution  thereof,  and such other information with respect to
such holder as, in the  reasonable  judgment of counsel for the  Registrant,  is
necessary to enable the Registrant to include in such registration statement all
material  facts  required  to  be  disclosed  with  respect  to  a  registration
thereunder.



                                      -12-





                  (h) A  registration  effected  under this  Section 10 shall be
effected at the  Registrant's  expense,  except for  underwriting  discounts and
commissions  and the fees and the expenses of counsel to the Designated  Holder,
and  the  Registrant  shall  provide  to  the  underwriters  such  documentation
(including  certificates,   opinions  of  counsel  and  "comfort"  letters  from
auditors) as is customary in connection with  underwritten  public  offerings as
such underwriters may reasonably require.

                  (i)  In connection with any registration effected under
this Section 10, the parties agree

                       (i) to indemnify each other and the  underwriters  in the
         customary manner,

                       (ii) to enter into an underwriting  agreement in form and
         substance  customary for transactions of such type with the Manager and
         the other underwriters participating in such offering, and

                       (iii)  to  take  all  further   actions  which  shall  be
         reasonably necessary to effect such registration and sale (including if
         the   Manager   deems  it   necessary,   participating   in   road-show
         presentations).

                  (j) The  Registrant  shall  be  entitled  to  include  (at its
expense)  additional  shares  of its  common  stock in a  registration  effected
pursuant  to this  Section 10 only if and to the extent the  Manager  determines
that such inclusion will not adversely  affect the prospects for success of such
offering.

                  11.  ADJUSTMENT  UPON  CHANGES  IN   CAPITALIZATION.   Without
limitation  to any  restriction  on BGE  contained  in this  Agreement or in the
Merger  Agreement,  in the event of any change in BGE Common  Stock by reason of
stock dividends,  splitups, mergers (other than the Merger),  recapitalizations,
combinations,  exchange of shares or the like,  the type and number of shares or
securities  subject to the BGE Option, and the purchase price per share provided
in  Section 1, shall be  adjusted  appropriately  to restore to PEPCO its rights
hereunder,  including the right to purchase from BGE (or its successors)  shares
of BGE Common Stock  representing  19.9% of the outstanding BGE Common Stock for
the aggregate  Exercise  Price  calculated  as of the date of this  Agreement as
provided in Section 1.

                  12. RESTRICTIVE LEGENDS. Each certificate  representing shares
of BGE  Common  Stock  issued  to PEPCO  hereunder,  and PEPCO  Shares,  if any,
delivered  to BGE at a  Closing,  shall  include a legend in  substantially  the
following form:

         THE SECURITIES REPRESENTED BY THIS CERTIFICATE HAVE NOT BEEN REGISTERED
         UNDER THE SECURITIES ACT OF 1933, AS AMENDED,  OR ANY STATE  SECURITIES
         OR BLUE SKY LAWS,


                                      -13-





         AND MAY BE REOFFERED OR SOLD ONLY IF SO  REGISTERED  OR IF AN EXEMPTION
         FROM SUCH  REGISTRATION IS AVAILABLE.  SUCH SECURITIES ARE ALSO SUBJECT
         TO  ADDITIONAL  RESTRICTIONS  ON TRANSFER AS SET FORTH IN THE BGE STOCK
         OPTION  AGREEMENT,  DATED AS OF SEPTEMBER 22, 1995, A COPY OF WHICH MAY
         BE OBTAINED FROM THE ISSUER UPON REQUEST.

It is understood and agreed that:

                       (i)  the  reference  to the  resale  restrictions  of the
         Securities  Act and  state  securities  or Blue Sky  laws in the  above
         legend  shall be  removed  by  delivery  of  substitute  certificate(s)
         without such  reference if PEPCO or BGE, as the case may be, shall have
         delivered  to the other  party a copy of a letter from the staff of the
         SEC, or an opinion of counsel,  in form and substance  satisfactory  to
         the other  party,  to the effect that such legend is not  required  for
         purposes of the Securities Act or such laws;

                       (ii) the reference to the provisions to this Agreement in
         the  above   legend   shall  be  removed  by  delivery  of   substitute
         certificate(s)  without such  reference if the shares have been sold or
         transferred  in compliance  with the  provisions of this  Agreement and
         under   circumstances  that  do  not  require  the  retention  of  such
         reference; and

                       (iii) the legend  shall be removed in its entirety if the
         conditions in the preceding clauses (i) and (ii) are both satisfied.

In addition, such certificates shall bear any other legend as may be required by
law.  Certificates  representing  shares sold in a  registered  public  offering
pursuant  to  Section 10 shall not be  required  to bear the legend set forth in
this Section 12.

                  13.   BINDING   EFFECT;   NO   ASSIGNMENT;   NO  THIRD   PARTY
BENEFICIARIES. (a) This Agreement shall be binding upon and inure to the benefit
of the parties hereto and their respective successors and permitted assigns.

                  (b)  Except  as  expressly  provided  for in  this  Agreement,
neither this  Agreement nor the rights or obligations of either party hereto are
assignable, except by operation of law, or with the written consent of the other
party.

                  (c) Nothing  contained in this Agreement,  express or implied,
is intended to confer  upon any person  other than the parties  hereto and their
respective  permitted assigns any rights or remedies of any nature whatsoever by
reason of this Agreement.

                  (d) Any Restricted  Shares sold by a party in compliance  with
the provisions of Section 10 shall,  upon  consummation of such sale, be free of
the restrictions imposed


                                      -14-





with respect to such shares by this Agreement, unless and until such party shall
repurchase  or otherwise  become the  beneficial  owner of such shares,  and any
transferee  of such shares shall not be entitled to the  registration  rights of
such party.

                  14.  SPECIFIC  PERFORMANCE.  The  parties  hereto  agree  that
irreparable  harm would  occur in the event that any of the  provisions  of this
Agreement were not performed in accordance  with their  specified  terms or were
otherwise  breached.  It is accordingly  agreed that the parties hereto shall be
entitled to an injunction or injunctions  to prevent  breaches of this Agreement
and to enforce  specifically the terms and provisions hereof in any court of the
United  States or any state having  jurisdiction,  this being in addition to any
other remedy to which they are entitled at law or equity.

                  15. VALIDITY.  (a) The invalidity or  unenforceability  of any
provision of this Agreement shall not affect the validity or  enforceability  of
the other  provisions  of this  Agreement,  which shall remain in full force and
effect.

                  (b) In the event any court or other competent  authority holds
any provisions of this Agreement to be null, void or unenforceable,  the parties
hereto shall  negotiate in good faith the execution and delivery of an amendment
to this Agreement in order, as nearly as possible, to effectuate,  to the extent
permitted  by law,  the  intent  of the  parties  hereto  with  respect  to such
provision and the economic effects thereof.

                  (c) If for any  reason  any such  court or  regulatory  agency
determines  that PEPCO is not  permitted to acquire,  or BGE is not permitted to
repurchase  pursuant to Section 7, the full number of shares of BGE Common Stock
provided  in Section 1 hereof (as the same may be  adjusted),  it is the express
intention of BGE to allow PEPCO to acquire or to require BGE to repurchase  such
lesser  number  of  shares  as may  be  permissible  without  any  amendment  or
modification hereof.

                  (d)  Each  party  agrees  that,  should  any  court  or  other
competent  authority  hold any provision of this  Agreement or part hereof to be
null, void or unenforceable,  or order any party to take any action inconsistent
herewith,  or not take any action required herein,  the other party shall not be
entitled  to specific  performance  of such  provision  or part hereof or to any
other remedy,  including but not limited to money damages,  for breach hereof or
of any other  provision  of this  Agreement or part hereof as the result of such
holding or order.

                  16. NOTICES.  All notices and other  communications  hereunder
shall be in writing and shall be deemed given if (a)  delivered  personally,  or
(b) if sent by overnight courier service (receipt confirmed in writing),  or (c)
if delivered by facsimile transmission with receipt confirmed), or (d) five days
after being mailed by registered or certified mail (return receipt


                                      -15-





requested)  to the parties in each case to the  following  addresses (or at such
other address for a party as shall be specified by like notice):

                  A.       If to PEPCO, to:

                           By Mail
                           and Hand:   1900 Pennsylvania Avenue, NW
                                       Washington, D.C.  20063

                                       Attention: Dennis R. Wraase
                                                  Senior Vice President-
                                                  Finance and Accounting
                                                  Fax: (202) 331-6314

                                                  William T. Torgerson
                                                  Senior Vice President-
                                                  Law & Governmental Relations,
                                                  General Counsel and Secretary
                                                  Fax: (202) 331-6314

                           with a copy to:

                                       LeBoeuf, Lamb, Greene, & MacRae, L.L.P.
                                       125 West 55th Street
                                       New York, New York  10019

                                       Attention: Douglas W. Hawes, Esq.
                                                  Fax: (212) 424-5800

                           and a copy to:

                                       Covington & Burling
                                       1201 Pennsylvania Avenue, N.W.
                                       Washington, D.C.  20044

                                       Attention: George B. Reid, Jr
                                                  Fax: (202) 662-6291



                  B.       If to BGE, to:

                           By Mail:    P.O. Box 1475
                                       Baltimore, MD  21203

                           By Hand:    Liberty and Lexington Streets
                                       Baltimore, MD  21201

                                       Attention: Charles W. Shivery
                                                  Vice President and CFO
                                                  Fax: (410) 234-5690


                                      -16-





                                                  David A. Brune, Esq.
                                                  General Counsel
                                                  Fax: (410) 234-5513

                           with a copy to:

                                       Winthrop, Stimson, Putnam & Roberts
                                       One Battery Park Plaza
                                       New York, New York  10004-1490

                                       Attention: Stephen R. Rusmisel, Esq.
                                                  Fax: (212) 858-1500

                  17.  GOVERNING LAW;  CHOICE OF FORUM.  This Agreement shall be
governed by and construed in  accordance  with the laws of the State of Maryland
applicable to agreements made and to be performed entirely within such State and
without regard to its choice of law principles.

                  18.      INTERPRETATION.

                  (a) When  reference  is made in this  Agreement  to  Articles,
Sections or Exhibits, such reference shall be to an Article,  Section or Exhibit
of this Agreement, as the case may be, unless otherwise indicated.

                  (b) The  table of  contents  and  headings  contained  in this
Agreement are for reference purposes and shall not affect in any way the meaning
or interpretation of the Agreement.

                  (c) Whenever the words  "include,"  "includes," or "including"
are used in this  Agreement,  they shall be deemed to be  followed  by the words
"without limitation."

                  (d)  Whenever  "or"  is used in this  Agreement  it  shall  be
construed in the nonexclusive sense.

                  19.  COUNTERPARTS;  EFFECT.  This Agreement may be executed in
one or more counterparts,  each of which shall be deemed to be an original,  but
all of which shall constitute one and the same agreement.

                  20. AMENDMENTS;  WAIVER.  This Agreement may be amended by the
parties  hereto and the terms and  conditions  hereof  may be waived  only by an
instrument in writing signed on behalf of each of the parties hereto, or, in the
case of a waiver,  by an  instrument  signed  on  behalf  of the  party  waiving
compliance.

                  21.  EXTENSION OF TIME PERIODS.  The time periods for exercise
of certain rights under Sections 2, 6 and 7 shall be extended:



                                      -17-





                  (a) to the extent necessary to obtain all regulatory approvals
for the exercise of such rights, and for the expiration of all statutory waiting
periods; and

                  (b) to the  extent  necessary  to avoid  any  liability  under
Section 16(b) of the Exchange Act by reason of such exercise.






















                      THIS SPACE INTENTIONALLY LEFT BLANK.







                                      -18-






                  IN WITNESS  WHEREOF,  the  parties  hereto  have  caused  this
Agreement to be executed by their respective duly authorized  officers as of the
date first above written.


                                             POTOMAC ELECTRIC POWER COMPANY


                                             /s/ EDWARD F. MITCHELL
                                             -----------------------------------
                                             Edward F. Mitchell
                                             Chairman of the Board and
                                               Chief Executive Officer



                                             BALTIMORE GAS AND ELECTRIC COMPANY


                                             /s/ CHRISTIAN H. POINDEXTER
                                             -----------------------------------
                                             Christian H. Poindexter
                                             Chairman of the Board and
                                               Chief Executive Officer


                                      -19-