Swap Agreement Confirmation between Credit Suisse International and Wells Fargo Bank, N.A. (as Trustee) for Adjustable Rate Mortgage Trust 2006-1

 CREDIT SUISSE INTERNATIONAL One Cabot Square, Telephone 020 7888 8888 London E14 4QJ www.credit-suisse.com CREDIT SUISSE FIRST BOSTON INTERNATIONAL One Cabot Square, Telephone 020 7888 8888 London E14 4QJ www.csfb.com CREDIT SUISSE FIRST BOSTON INTERNATIONAL One Cabot Square, Telephone 020 7888 8888 London E14 4QJ www.csfb.com Facsimile Cover Sheet To: Wells Fargo Bank, N.A., not in its individual capacity but solely as trustee on behalf of the supplemental interest trust created pursuant to the PSA Attention: Heakyung Chung, CSIN Marketer Fax number: To be hand delivered by Heakyung Chung Date: 28 February 2006 Pages (including cover page): 7 Our Reference No: External ID: 9287309 / Risk ID: 9287309 Credit Suisse International has entered into a transaction with you as attached. Please find attached a letter agreement (the "Confirmation") which confirms the terms and conditions of the above transaction. If you agree with the terms specified therein, please arrange for the Confirmation to be signed by your authorised signatories and return a signed copy to this office to the facsimile listed below. For Interest Rate Products: For Equity Derivatives: Telephone Numbers: (212) 538-9370 Telephone numbers: (212) 538-4437 / Facsimile number: (917) 326-8603 ###-###-#### / (212) 325-5119 Email: Facsimile number: (212) 325-8173 ***@*** For Credit Derivatives: Telephone Numbers: (212) 538-9370 Facsimile number: (917) 326-8603 Email:  ***@*** We are delighted to have entered into this transaction with you. CONFIDENTIALITY NOTICE: This facsimile is intended only for the use of the individual or entity to which it is addressed and may contain information which is privileged and confidential. If the reader of this message is not the intended recipient or an employee or agent responsible for delivering the message to the intended recipient, you are hereby notified that any dissemination, distribution or copying of this communication is strictly prohibited. If you have received this communication in error, please notify us immediately by telephone and return the original message to us by mail. Thank you. Registered Office as above Registered with unlimited liability in England under No. 2500199 Authorised and Regulated by the Financial Services Authority VAT No: GB ###-###-#### 41 CREDIT SUISSE INTERNATIONAL One Cabot Square, Telephone 020 7888 8888 London E14 4QJ www.credit-suisse.com CREDIT SUISSE FIRST BOSTON INTERNATIONAL One Cabot Square, Telephone 020 7888 8888 London E14 4QJ www.csfb.com CREDIT SUISSE FIRST BOSTON INTERNATIONAL One Cabot Square, Telephone 020 7888 8888 London E14 4QJ www.csfb.com 28 February 2006 Wells Fargo Bank, NA, not individually, but solely as trustee on behalf of the supplemental interest trust created under the PSA for Adjustable Rate Mortgage Trust 2006-1 9062 Old Annapolis Road Columbia, Maryland 21045 Attn: Diane TenHoopen Fax: 410 ###-###-#### External ID: 9287309 ______________________________________________________________________________ Dear Sir/Madam: The purpose of this letter agreement (this "Confirmation") is to confirm the terms and conditions of the Transaction entered into between us on the Trade Date specified below (the "Transaction"). This Confirmation constitutes a "Confirmation" as referred to in the Agreement specified below. In this Confirmation "Party A" means Credit Suisse International and "Party B" means Wells Fargo Bank, N.A., not in its individual capacity but solely as trustee of the supplemental interest trust created pursuant to the PSA for Adjustable Rate Mortgage Trust 2006-1 (the "Trust"). 1. The definitions and provisions contained in the 2000 ISDA Definitions (as published by the International Swaps and Derivatives Association, Inc.) (the "Definitions") are incorporated into this Confirmation. In the event of any inconsistency between those definitions and provisions and this Confirmation, this Confirmation will govern. References herein to a "Transaction" shall be deemed to be references to a "Swap Transaction" for the purposes of the Definitions. This Confirmation supplements, forms part of, and is subject to, the 1992 ISDA Master Agreement dated as of February 28, 2006 as amended and supplemented from time to time (the "Agreement"), between you and us. All provisions contained in the Agreement govern this Confirmation except as expressly modified below. Party A and Party B each represents to the other that it has entered into this Swap Transaction in reliance upon such tax, accounting, regulatory, legal, and financial advice as it deems necessary and not upon any view expressed by the other. Terms used herein and not otherwise defined herein in the Definitions or the Agreement, shall have the meanings ascribed to them in the Pooling and Servicing Agreement relating to Adjustable Rate Mortgage Trust 2006-1 between Credit Suisse First Boston Mortgage Securities Corp., as Depositor, DLJ Mortgage Capital, Inc., as Seller, Wells Fargo Bank, N.A., as Master Servicer, Servicer, Back-Up Servicer and Trust Administrator, Select Portfolio Servicing Inc., as a Servicer and as Special Servicer, and U.S. Bank National Association, as Trustee, dated as of February 1, 2006, as amended from time to time (the "PSA"). In the event of an inconsistency between the terms defined in the PSA and this Confirmation, this Confirmation will govern. Registered Office as above Registered with unlimited liability in England under No. 2500199 Authorised and Regulated by the Financial Services Authority VAT No: GB ###-###-#### 41 CREDIT SUISSE INTERNATIONAL One Cabot Square, Telephone 020 7888 8888 London E14 4QJ www.credit-suisse.com 2. The terms of the particular Swap Transaction to which this Confirmation relates are as follows: Trade Date: February 24, 2006 Effective Date: February 28, 2006 Termination Date: The earliest of (a) the Distribution Date on which the Certificate Principal Balance of the Class 6-A-1 Certificates has been reduced to zero, (b) the purchase by the Terminating Entity of all of the Mortgage Loans in Loan Group 6 and (c) the Distribution Date in March, 2036. Floating Rate Payer: In respect of each Party A Floating Amount, Party A and in respect of each Party B Floating Amount, Party B. Notional Amount: In respect of each Payment Date, the lesser of (1) the aggregate Class Principal Balance of the Class 6-A-1 Certificates for the immediately preceding Distribution Date after giving effect to distributions on such Distribution Date (or as of the Effective Date for the first Distribution Date) and (2) the Aggregate Loan Group Balance for Loan Group 6 for the related Distribution Date, provided that the Notional Amount with respect to the initial Payment Date will be USD USD 228,635,000. Period End Date: The 25th of each month, commencing on 25 March 2006, subject to adjustment in accordance with the Following Business Day Convention. Payment Dates: One Business Day prior to each Period End Date, commencing in the calendar month of March 2006. Floating Rate Day Count Actual/360 Fraction: Business Days: New York Party A Floating Amounts Party A Floating Amounts: In respect of each Payment Date, the product of: (a) the greater of: (i) zero; and (ii) the Formula Rate applicable to the Class 6-A-1 Certificates in respect of the related Distribution Date, less the excess of (a) the Group 6 Net Funds Cap in respect of the related Distribution Date over (b) the Swap Fee Rate; (b) the Notional Amount; and (c) the Floating Rate Day Count Fraction. Party B Floating Amounts Party B Floating Amounts: In respect of each Payment Date, the product of: (a) the Swap Fee Rate; (b) the Notional Amount; and (c) the Floating Rate Day Count Fraction. Swap Fee Rate: 0.05 per cent per annum in respect of each Calculation Period falling in the period from, and including, the Effective Date to, but excluding, the Optional Termination Date, and 0.10 per cent. per annum in respect of each Calculation Period (if any) falling in the period from, and including, the Optional Termination Date to, but excluding, the Termination Date. 3. Other provisions: Swap Fee Reimbursement Amount: In respect of each Payment Date, an amount equal to the Swap Fee Amount for such Payment Date minus the amount of the Net Swap Payment paid by Party B for such Payment Date. Swap Counterparty Reimbursement In respect of each Payment Date or Amount: Distribution Date, the sum of (a) the Party A Floating Amount in respect of such Payment Date minus the amount of any Swap Fee Reimbursement Amount, or portion thereof, paid to the Swap Counterparty on such date, (b) any portion of the amount described in clause (a) that remains unpaid as of the date immediately after such prior Payment Date and (c) interest in respect of any such unpaid amounts described in clause (b), charged at a rate (calculated using the Floating Rate Day Count Fraction) equal to the Formula Rate in respect of the Class 6-A-1 Certificates for the related Distribution Date. On each Payment Date, Party B shall pay to Party A the Swap Fee Reimbursement Amount and the Swap Counterparty Reimbursement Amount in respect of such Payment Date (if any) in accordance with the priorities of distributions set forth in the PSA, provided that a failure by Party B to make, when due, any payment of the Swap Counterparty Reimbursement Amount or the Swap Fee Reimbursement Amount under this Transaction shall not constitute a Failure to Pay or Deliver in respect of Party B unless such failure occurs in breach of the PSA. Calculation of Loss following Upon the designation of an Early Termination Event/Event of Termination Date in respect of this Default: Transaction, the relevant party for the purposes of determining a party's Loss in respect of this Transaction shall, in all circumstances, be Party A. In calculating a party's Loss, Party A shall take into account the anticipated amortization of the Certificate Principal Balance of the Class 6-A-1 Certificates for all Calculation Periods that would otherwise have fallen after such Early Termination Date. Formula Rate: The Formula Rate in respect of this transaction shall be equal to the Formula Rate as determined under the PSA. The Formula Rate for the Class 6-A-1 Certificates is LIBOR (as defined in the PSA) for such Distribution Date plus (A) on or prior to the Optional Termination Date, 0.13% per annum or (B) after the Optional Termination Date, 0.26% per annum. Distribution Date: On the 25th day of each month, or if such 25th day is not a Business Day (as defined in the PSA), the Business Day (as defined in the PSA) immediately following such 25th day. 4. Account details: Payments to Party A: As advised separately in writing Payments to Party B: Wells Fargo Bank, NA San Francisco, CA ABA 121-000-248 Account Number: 3970771416 Account Name: Corporate Trust Clearing FFC: 50894601, ARMT 2006-1 Class 6-A-1 Swap Account Credit Suisse International is regulated and authorised by The Financial Services Authority and has entered into this Transaction as principal. The time at which the above Transaction was executed will be notified to Party B on request. For the purpose of facilitating this Transaction, an Affiliate of CSi, which is organized in the United States of America (the "Agent"), has acted as agent for CSi. The Agent is not a principal with respect to this Transaction and shall have no responsibility or liability to the parties as a principal with respect to this Transaction. Please confirm that the foregoing correctly sets forth the terms of our agreement by executing the copy of this Confirmation enclosed for that purpose and returning it to us. Yours faithfully, Credit Suisse International By:_____________________________ Name: Title: Confirmed as of the date first written above: Wells Fargo Bank, N.A., not in its individual capacity, but solely as trustee of the supplemental interest trust created pursuant to the PSA for Adjustable Rate Mortgage Trust 2006-1 By:________________________________ Name: Title: Our Reference No: External ID: 9287309 / Risk ID: 9287309