<PAGE>

                                                                     EXHIBIT 4.7

                 FORM OF SERIES B CAPITAL SECURITY CERTIFICATE

          IF THE SERIES B CAPITAL SECURITIES CERTIFICATE IS TO BE A GLOBAL
SECURITIES CERTIFICATE, INSERT-- [THIS SERIES B CAPITAL SECURITY IS A GLOBAL
CAPITAL SECURITY WITHIN THE MEANING OF THE AMENDED AND RESTATED DECLARATION OF
TRUST (THE "DECLARATION") HEREINAFTER REFERRED TO AND IS REGISTERED IN THE NAME
OF THE DEPOSITORY TRUST COMPANY (THE "CLEARING AGENCY") OR A NOMINEE OF THE
CLEARING AGENCY. THIS SERIES B CAPITAL SECURITY IS EXCHANGEABLE FOR SERIES B
CAPITAL SECURITIES REGIS TERED IN THE NAME OF A PERSON OTHER THAN THE CLEARING
AGENCY OR ITS NOMINEE ONLY IN THE LIMITED CIRCUMSTANCES DESCRIBED IN THE
DECLARATION AND NO TRANSFER OF THIS SERIES B CAPITAL SECURITY (OTHER THAN A
TRANSFER OF THIS SERIES B CAPITAL SECURITY AS A WHOLE BY THE CLEARING AGENCY TO
A NOMINEE OF THE CLEARING AGENCY OR BY A NOMINEE OF THE CLEARING AGENCY TO THE
CLEARING AGENCY OR ANOTHER NOMINEE OF THE CLEARING AGENCY) MAY BE REGISTERED
EXCEPT IN LIMITED CIRCUMSTANCES.

          UNLESS THIS SERIES B CAPITAL SECURITY IS PRESENTED BY AN AUTHORIZED
REPRESENTATIVE OF THE CLEARING AGENCY TO ASTORIA CAPITAL TRUST I (THE "TRUST")
OR ITS AGENT FOR REGISTRATION OF TRANSFER, EXCHANGE OR PAYMENT, AND ANY SERIES B
CAPITAL SECURITY ISSUED IS REGISTERED IN THE NAME OF CEDE & CO. OR SUCH OTHER
NAME AS REQUESTED BY AN AUTHORIZED REPRESENTATIVE OF THE CLEARING AGENCY AND ANY
PAYMENT HEREON IS MADE TO CEDE & CO., ANY TRANSFER, PLEDGE OR OTHER USE HEREOF
FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL SINCE THE REGISTERED
OWNER HEREOF, CEDE & CO., HAS AN INTEREST HEREIN.]

          THE HOLDER OF THIS SERIES B CAPITAL SECURITY BY ITS ACCEPTANCE HEREOF
ALSO AGREES, REPRESENTS AND WARRANTS THAT IT IS NOT AN EMPLOYEE BENEFIT,
INDIVIDUAL RETIREMENT ACCOUNT OR OTHER PLAN OR ARRANGEMENT SUBJECT TO TITLE I OF
THE EMPLOYEE RETIREMENT INCOME SECURITY ACT OF 1974, AS AMENDED ("ERISA"), OR
SECTION 4975 OF THE INTERNAL REVENUE CODE OF 1986, AS AMENDED (THE "CODE") (EACH
A "PLAN"), OR AN ENTITY WHOSE UNDERLYING ASSETS INCLUDE "PLAN ASSETS" BY REASON
OF ANY PLAN'S INVESTMENT IN THE ENTITY AND NO PERSON INVESTING "PLAN ASSETS" OF
ANY PLAN MAY ACQUIRE OR HOLD THE SERIES B CAPITAL SECURITIES OR ANY INTEREST
THEREIN, UNLESS SUCH PURCHASER OR HOLDER IS ELIGIBLE FOR THE EXEMPTIVE RELIEF
AVAILABLE UNDER U.S. DEPARTMENT OF LABOR PROHIBITED TRANSACTION CLASS EXEMPTION
96-23, 95-60, 91-38, 90-1 OR 84-14 OR ANOTHER APPLICABLE EXEMPTION OR ITS
PURCHASE AND HOLDING OF SERIES B CAPITAL SECURITIES IS NOT PROHIBITED BY SECTION
406 OF ERISA OR SECTION 4975 OF THE CODE WITH RESPECT TO SUCH PURCHASE OR
HOLDING. ANY PURCHASER OR HOLDER OF THE SERIES B CAPITAL SECURITIES OR ANY
INTEREST THEREIN WILL BE
<PAGE>

DEEMED TO HAVE REPRESENTED BY ITS PURCHASE AND HOLDING THEREOF THAT EITHER (i)
IT IS NOT AN EMPLOYEE BENEFIT PLAN WITHIN THE MEANING OF SECTION 3(3) OF ERISA,
OR A PLAN TO WHICH SECTION 4975 OF THE CODE IS APPLICABLE, A TRUSTEE OR OTHER
PERSON ACTING ON BEHALF OF AN EMPLOYEE BENEFIT PLAN OR PLAN, OR ANY OTHER PERSON
OR ENTITY USING THE ASSETS OF ANY EMPLOYEE BENEFIT PLAN OR PLAN TO FINANCE SUCH
PURCHASE, OR (ii) SUCH PURCHASE WILL NOT RESULT IN A PROHIBITED TRANSACTION
UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE FOR WHICH THERE IS NO
APPLICABLE STATUTORY OR ADMINISTRATIVE EXEMPTION.

     THE SERIES B CAPITAL SECURITIES WILL BE ISSUED AND MAY BE TRANSFERRED ONLY
IN BLOCKS HAVING A LIQUIDATION AMOUNT OF NOT LESS THAN $100,000 (100 SERIES B
CAPITAL SECURITIES) AND MULTIPLES OF $1,000 IN EXCESS THEREOF. ANY ATTEMPTED
TRANSFER OF SERIES B CAPITAL SECURITIES IN A BLOCK HAVING A LIQUIDATION AMOUNT
OF LESS THAN $100,000 (100 SERIES B CAPITAL SECURITIES) SHALL BE DEEMED TO BE
VOID AND OF NO LEGAL EFFECT WHATSOEVER. ANY SUCH PURPORTED TRANSFEREE SHALL BE
DEEMED NOT TO BE THE HOLDER OF SUCH SERIES B CAPITAL SECURITIES FOR ANY PURPOSE,
INCLUDING, BUT NOT LIMITED TO, THE RECEIPT OF DISTRIBUTIONS ON SUCH SERIES B
CAPITAL SECURITIES, AND SUCH PURPORTED TRANSFEREE SHALL BE DEEMED TO HAVE NO
INTEREST WHATSOEVER IN SUCH SERIES B CAPITAL SECURITIES.
<PAGE>

Certificate Number: _____                          Aggregate Liquidation Amount:
CUSIP Number: 04626K AC5                           $______________



               Certificate Evidencing Exchange Capital Securities

                                       of

                             Astoria Capital Trust I

                       9.75% Capital Securities, Series B
                (liquidation amount $1,000 per Capital Security)

          Astoria Capital Trust I, a statutory business trust created under the
laws of the State of Delaware (the "Trust"), hereby certifies that [Cede & Co.]1
(the "Holder") is the registered owner of $__________ in aggregate liquidation
amount of Capital Securities of the Trust representing undivided preferred
beneficial interests in the assets of the Trust designated the 9.75% Capital
Securities, Series B (liquidation amount $1,000 per Capital Security) (the
"Exchange Capital Securities"). The Exchange Capital Securities are transferable
on the books and records of the Trust, in person or by a duly authorized
attorney, upon surrender of this certificate duly endorsed and in proper form
for transfer. The designation, rights, privileges, restrictions, preferences and
other terms and provisions of the Exchange Capital Securities represented hereby
are issued and shall in all respects be subject to the provisions of the Amended
and Restated Declaration of Trust, dated as of October 28, 1999, as the same may
be amended from time to time (the "Declaration"), including the designation of
the terms of the Exchange Capital Securities as set forth in Annex I to the
Declaration. Capitalized terms used but not defined herein shall have the
meaning given them in the Declaration. The Sponsor will provide a copy of the
Declaration, the Capital Securities Guarantee and the Indenture (including any
supplemental indenture) to a Holder without charge upon written request to the
Trust at its principal place of business.

          Upon receipt of this Certificate, the Holder is bound by the
Declaration and is entitled to the benefits thereunder and to the benefits of
the Capital Securities Guarantee to the extent provided therein.

          By acceptance hereof, the Holder agrees, for United States federal
income tax purposes, to treat the Debentures as indebtedness and the Exchange
Capital Securities as evidence of indirect beneficial ownership in the
Debentures.



--------------
     1 Insert in Global Security only.
<PAGE>

          IN WITNESS WHEREOF, the Trust has executed this certificate this _____
day of ______________ , 2000.


                             ASTORIA CAPITAL TRUST I


                                          By: ____________________________
                                              Monte N. Redman
                                              Administrative Trustee



                PROPERTY TRUSTEE'S CERTIFICATE OF AUTHENTICATION

     This is one of the 9.75% Capital Securities, Series B of Astoria Capital
Trust I referred to in the within-mentioned Declaration.

Dated: ______________ , 2000.

                                          WILMINGTON TRUST COMPANY,
                                          not in its individual capacity but
                                          solely as Property Trustee


                                          By: ____________________________
                                              Authorized Signatory
<PAGE>

          Distributions on each Exchange Capital Security will be payable at a
fixed rate per annum of 9.75% (the "Coupon Rate") of the liquidation amount of
$1000 per Exchange Capital Security, such rate being the rate of interest
payable on the Debentures to be held by the Property Trustee. Distributions in
arrears for more than one semi-annual period will bear interest thereon
compounded semi-annually at the Coupon Rate (to the extent permitted by
applicable law). The term "Distributions," as used herein, includes such cash
distributions and any and all such interest, if any, payable unless otherwise
stated. A Distribution is payable only to the extent that payments are made in
respect of the Debentures held by the Property Trustee and to the extent the
Property Trustee has funds legally available therefor.

          Distributions on the Exchange Capital Securities will be cumulative,
will accumulate from the most recent date to which Distributions have been paid
or, if no Distributions have been paid, from October 28, 1999 and will be
payable semi-annually in arrears, on May 1/st/ and November 1/st/ of each year,
commencing May 1, 2000, except as otherwise described below. Distributions will
be computed on the basis of a 360-day year of twelve 30-day months. As long as
no Event of Default has occurred and is continuing under the Indenture, the
Debenture Issuer has the right under the Indenture to defer payments of interest
by extending the interest payment period at any time and from time to time on
the Debentures for a period not exceeding 10 consecutive semi-annual calendar
periods, including the first such semi-annual period during such extension
period (each an "Extension Period"), provided that no Extension Period shall end
                                     -------- ----
on a date other than an Interest Payment Date for the Debentures or extend
beyond the Maturity Date of the Debentures. As a consequence of such deferral,
Distributions will also be deferred. Notwithstanding such deferral, semi-annual
Distributions will continue to accumulate with interest thereon (to the extent
permitted by applicable law, but not at a rate exceeding the rate of interest
then accruing on the Debentures) at the Coupon Rate compounded semi-annually
during any such Extension Period. Prior to the termination of any Extension
Period, the Debenture Issuer may further defer payments of interest by further
extending such Extension Period; provided that such Extension Period, together
                                 -------- ----
with all such previous and further extensions within such Extension Period, may
not (i) exceed 10 consecutive semi-annual periods, including the first semi-
annual period during such Extension Period, (ii) end on a date other than an
Interest Payment Date for the Debentures or (iii) extend beyond the Maturity
Date of the Debentures. Payments of accumulated Distributions will be payable to
Holders as they appear on the books and records of the Trust on the record date
immediately preceding the end of the Extension Period. Upon the termination of
any Extension Period and the payment of all amounts then due, the Debenture
Issuer may commence a new Extension Period, subject to the above requirements.

          Subject to receipt by the Sponsor of any and all required regulatory
approvals and to certain other conditions set forth in the Declaration and the
Indenture, the Property Trustee may, at the direction of the Sponsor, at any
time dissolve the Trust and after satisfaction of liabilities to creditors of
the Trust as provided by applicable law, cause the Debentures to be distributed
to the Holders of the Securities in liquidation of the Trust or, simultaneously
with any redemption of the Debentures, cause a Like Amount of the Securities to
be redeemed by the Trust.

          The Exchange Capital Securities shall be redeemable as provided in the
Declaration.
<PAGE>

               -------------------------------------------------

                                   ASSIGNMENT

               -------------------------------------------------


FOR VALUE RECEIVED, the undersigned hereby assigns and transfers this Exchange
Capital Security Certificate to:

--------------------------------------------------------------------------------
--------------------------------------------------------------------------------
--------------------------------------------------------------------------------
           (Assignee's social security or tax identification number)


--------------------------------------------------------------------------------
--------------------------------------------------------------------------------
--------------------------------------------------------------------------------
                       (Address and zip code of assignee)


and irrevocably appoints

--------------------------------------------------------------------------------
--------------------------------------------------------------------------------
------------------------------------------------------------------------- agent
to transfer this Exchange Capital Security Certificate on the books of the
Trust. The agent may substitute another to act for him or her.

Date: __________________

Signature:_________________________________________
(Sign exactly as your name appears on the other side of this Exchange Capital
Security Certificate)

Signature Guarantee: ______________________________




---------------------------
     Signature must be guaranteed by an "eligible guarantor institution" that is
     a bank, stockbroker, savings and loan association or credit union meeting
     the requirements of the Registrar, which requirements include membership or
     participation in the Securities Transfer Agents Medallion Program ("STAMP")
     or such other "signature guarantee program" as may be determined by the
     Registrar in addition to, or in substitution for, STAMP, all in accordance
     with the Securities Exchange Act of 1934, as amended.
<PAGE>

                           COMMON SECURITY CERTIFICATE

         THIS COMMON SECURITY HAS NOT BEEN REGISTERED UNDER THE
SECURITIES ACT OF 1933, AS AMENDED (THE "SECURITIES ACT"), OR ANY STATE
SECURITIES LAWS OR ANY OTHER APPLICABLE SECURITIES LAW. NEITHER THIS
COMMON SECURITY NOR ANY INTEREST OR PARTICIPATION HEREIN MAY BE
REOFFERED, SOLD, ASSIGNED, TRANSFERRED, PLEDGED, ENCUMBERED OR
OTHERWISE DISPOSED OF IN THE ABSENCE OF SUCH REGISTRATION OR UNLESS
SUCH TRANSACTION IS EXEMPT FROM, OR NOT SUBJECT TO, REGISTRATION.

         THE HOLDER OF THIS COMMON SECURITY BY ITS ACCEPTANCE HEREOF
AGREES TO OFFER, SELL OR OTHERWISE TRANSFER THIS COMMON SECURITY,
PRIOR TO THE DATE (THE "RESALE RESTRICTION TERMINATION DATE") WHICH IS
TWO YEARS AFTER THE LATER OF THE ORIGINAL ISSUANCE DATE HEREOF AND THE
LAST DATE ON WHICH ASTORIA FINANCIAL CORPORATION (THE "CORPORATION")
OR ANY "AFFILIATE" OF THE CORPORATION WAS THE OWNER OF THIS COMMON
SECURITY (OR ANY PREDECESSOR OF THIS COMMON SECURITY) ONLY (A) TO THE
CORPORATION, (B) PURSUANT TO A REGISTRATION STATEMENT WHICH HAS BEEN
DECLARED EFFECTIVE UNDER THE SECURITIES ACT, (C) SO LONG AS  THIS COMMON
SECURITY IS ELIGIBLE FOR RESALE PURSUANT TO RULE 144A UNDER THE
SECURITIES ACT ("RULE 144A"), TO A PERSON IT REASONABLY BELIEVES IS A
"QUALIFIED INSTITUTIONAL BUYER" (AS DEFINED IN RULE 144A) THAT PURCHASES
FOR ITS OWN ACCOUNT OR FOR THE ACCOUNT OF A QUALIFIED INSTITUTIONAL
BUYER TO WHOM NOTICE IS GIVEN THAT THE TRANSFER IS BEING MADE IN
RELIANCE ON RULE 144A, (D) TO AN INSTITUTIONAL "ACCREDITED INVESTOR"
WITHIN THE MEANING OF SUBPARAGRAPH (a)(1), (2), (3) OR (7) OF RULE 501 UNDER
THE SECURITIES ACT THAT IS ACQUIRING THIS COMMON SECURITY FOR ITS OWN
ACCOUNT, OR FOR THE ACCOUNT OF SUCH AN INSTITUTIONAL ACCREDITED
INVESTOR, FOR INVESTMENT PURPOSES AND NOT WITH A VIEW TO, OR FOR OFFER
OR SALE IN CONNECTION WITH, ANY DISTRIBUTION IN VIOLATION OF THE
SECURITIES ACT, OR (E) PURSUANT TO ANY OTHER AVAILABLE EXEMPTION FROM
THE REGISTRATION REQUIREMENTS UNDER THE SECURITIES ACT, SUBJECT TO THE
RIGHT OF ASTORIA CAPITAL TRUST I (THE "TRUST") AND THE CORPORATION PRIOR
TO ANY SUCH OFFER, SALE OR TRANSFER (i) PURSUANT TO CLAUSE (D) OR (E) TO
REQUIRE THE DELIVERY OF AN OPINION OF COUNSEL, CERTIFICATIONS AND/OR
OTHER INFORMATION SATISFACTORY TO EACH OF THEM. SUCH HOLDER FURTHER
AGREES THAT IT WILL DELIVER TO EACH PERSON TO WHOM THIS COMMON
SECURITY IS TRANSFERRED A NOTICE SUBSTANTIALLY TO THE EFFECT OF THIS
LEGEND.