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                                                                     Exhibit 4.2


AMBAC                                        Ambac Assurance Corporation
                                             c/o CT Corporation
                                             44 East Mifflin Street,
                                             Madison, Wisconsin 53703
                                             Administrative Office:
CERTIFICATE GUARANTY INSURANCE POLICY        One State Street Plaza,
                                             New York, New York 10004
                                             Telephone: (212) 668-0340

Insured Obligations:  $517,500,000           Policy Number:  AB0263BE

Advanta Mortgage Loan Trust 1999-2,
Advanta Mortgage Loan Asset-Backed
Certificates, Series 1999-2, Class A-1,
Class A-2, Class A-3, Class A-4, Class A-5,
Class A-6 and Class A-7

                                             Premium: Calculated as set forth in
                                             Certificate Guaranty Insurance
                                             Policy Endorsement attached hereto
                                             and made a part hereof

AMBAC ASSURANCE CORPORATION (AMBAC) A Wisconsin Stock Insurance Company in
consideration of the payment of the premium and subject to the terms of this
Policy, hereby agrees unconditionally and irrevocably to pay to the Trustee for
the benefit of the Holders of the Insured Obligations, that portion of the
Insured Amounts which shall become Due for Payment but shall be unpaid by reason
of Nonpayment.

Ambac will make such payments to the Trustee from its own funds on the later of
(a) one (1) Business Day following notification to Ambac of Nonpayment or (b)
the Business Day on which the Insured Amounts are Due for Payment. Such payments
of principal or interest shall be made only upon presentation of an instrument
of assignment in form and substance satisfactory to Ambac, transferring to Ambac
all rights under such Insured Obligations to receive the principal of and
interest on the Insured Obligation. Ambac shall be subrogated to all the
Holders' rights to payment on the Insured Obligations to the extent of the
insurance disbursements so made. Once payments of the Insured Amounts have been
made to the Trustee, Ambac shall have no further obligation hereunder in respect
of such Insured Amounts.

In the event the Trustee for the Insured Obligations has notice that any payment
of principal or interest on an Insured Obligation which has become Due for
Payment and which is made to a Holder by or on behalf of the Trustee has been
deemed a preferential transfer and theretofore recovered from its Holder
pursuant to the United States Bankruptcy Code in accordance with a final,
nonappealable order of a court of competent jurisdiction, such Holder will be
entitled to payment from Ambac to the extent of such recovery if sufficient
funds are not otherwise available.

This Policy is noncancelable by Ambac for any reason, including failure to
receive payment of any premium due hereunder. The premium on this Policy is not
refundable for any reason. This Policy does not insure against loss of any
prepayment or other acceleration payment which at any time may become due in
respect of any Insured Obligation, other than at the sole option of Ambac, nor
against any risk other than Nonpayment, including failure of the Trustee to make
any payment due Holders of Insured Amounts.

To the fullest extent permitted by applicable law, Ambac hereby waives and
agrees not to assert any and all rights and defenses, to the extent such rights
and defenses may be available to Ambac, to avoid payment of its obligations
under this Policy in accordance with the express provisions hereof.

Any capitalized terms not defined herein shall have the meaning given such terms
in the endorsement attached hereto or in the Agreement.

In witness whereof, Ambac has caused this Policy to be affixed with its
corporate seal and to be signed by its duly authorized officers in facsimile to
become effective as their original signatures and binding upon Ambac by virtue
of the countersignature of its duly authorized representative.


/s/ P. Lassiter                                  /s/ Stephen D. Cooke
- ---------------                                  --------------------
President                                        Secretary

                                                 /s/ [Authorized Representative]
                                                 -------------------------------
Effective Date: June 3, 1999                     Authorized Representative