Exhibit
4.28



EXECUTION VERSION



NOTICE OF ESTABLISHMENT
OF UNCOMMITTED REVOLVING FACILITY COMMITMENTS



| | To: | Bank of America Merrill Lynch International Limited as Agent as defined in the Agreement (defined
below)
| | --- | --------------------------------------------------------------------------------------------------------



29
January 2016



Dear Sirs,



US$1,500,000,000
facilities agreement originally dated 2 November 2012 between, among others, Syngenta AG as Company, Bank of America Merrill Lynch
International Limited (formerly known as Banc of America Securities Limited), Banco Santander, S.A., Citigroup Global Markets Limited,
Credit Suisse AG, Deutsche Bank AG, HSBC Bank plc, UBS AG and Unicredit Bank AG as Arranger and Bank of America Merrill Lynch International
Limited (formerly known as Banc of America Securities Limited) as Agent as amended pursuant to an amendment letter dated 28 January
2016 (theAgreement)



| | 1. | Interpretation
| | -- | --------------



| | (a) | We refer to the Agreement. Capitalised terms defined in the Agreement have
the same meaning when used in this notice unless expressly defined in this notice.
| | --- | -------------------------------------------------------------------------------------------------------------------------------------------------------------



| | (b) | The provisions of clause 1.2 (Construction) of the Agreement apply to this
notice as though they were set out in full in this notice except that references to the Agreement are to be construed as references
to this notice.
| | --- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------



| | 2. | Establishment of Uncommitted Revolving Facility Commitment
| | -- | ----------------------------------------------------------



| | (a) | Pursuant to clause 2.2 (Uncommitted Revolving Facility) of the Agreement,
the Company requests the establishment of an Uncommitted Revolving Facility Commitment in an aggregate amount equal to USD 1,000,000,000
(the Uncommitted Revolving Facility Commitment).
| | --- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------



| | (b) | The Company confirms that no Default is continuing or would result from
the establishment of the Uncommitted Revolving Facility Commitment.
| | --- | -------------------------------------------------------------------------------------------------------------------------------------------



| | (c) | Each Uncommitted Revolving Facility Lender will assume all of the obligations
corresponding to the Uncommitted Revolving Facility Commitment in the amount in the Base Currency set opposite its name under the
heading “Uncommitted Revolving Facility Commitment” in the Schedule to this notice.
| | --- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------



| | (d) | The establishment and assumption of the Uncommitted Revolving Facility Commitment
shall take effect on the date on which the conditions set in paragraph (b) of clause 2.2 (Uncommitted Revolving Facility Commitments)
of the Agreement in relation to each Uncommitted Revolving Facility Lender have been satisfied (the Assumption Date). The
Agent shall notify the Company and the Uncommitted Revolving Facility Lenders promptly following the occurrence of the Assumption
Date.
| | --- | -----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------



| | (e) | The Agent shall promptly notify the Lenders of the establishment of the Uncommitted
Revolving Facility Commitment.
| | --- | ------------------------------------------------------------------------------------------------------------------



| | (f) | The Company shall pay to each Uncommitted Revolving Facility Lender a fee in the amount and times
agreed in a Fee Letter.
| | --- | -------------------------------------------------------------------------------------------------------------------------



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| | 3. | Miscellaneous
| | -- | -------------



This notice may be executed
in any number of counterparts and this has the same effect as if the signatures on the counterparts were on a single copy of this
notice.



| | 4. | Governing law
| | -- | -------------



This notice and any non-contractual
obligations arising out of or in connection with it are governed by English law.



2




Yours faithfully,



|/s/ Daniel
    Michaelis | /s/ Nicholas
    Zuercher
|------------------------ | -------------------------





For



Syngenta AG



as Company













Syngenta AG – Signature Page to

Notice of Uncommitted Revolving



Facility Commitments



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FORM OF ACKNOWLEDGEMENT



We agree to the terms of this notice.



/s/ Kevin Day



Kevin Day



Vice President



For



Bank of America Merrill Lynch International Limited



for itself and as Agent of the other Finance Parties



Date:	29 January 2016













Syngenta AG – Signature Page to

Notice of Uncommitted Revolving



Facility Commitments





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SCHEDULE



UNCOMMITTED REVOLVING FACILITY COMMITMENTS



|Name of Uncommitted Revolving Facility Lender                                                                         | Uncommitted Revolving Facility Commitment
        
        (USD)
|--------------------------------------------------------------------------------------------------------------------- | ----------------------------------------------------------------
|Goldman Sachs Bank USA                                                                                                | 213,636,363.64                                                  
|JPMorgan Chase Bank, N.A.                                                                                             | 213,636,363.64                                                  
|Banco Santander, S.A.                                                                                                 | 63,636,363.64                                                   
|Citibank, N.A., London Branch                                                                                         | 63,636,363.64                                                   
|Credit Suisse AG                                                                                                      | 63,636,363.64                                                   
|Deutsche Bank Luxembourg S.A.                                                                                         | 63,636,363.64                                                   
|UniCredit Luxembourg S.A.                                                                                             | 63,636,363.64                                                   
|UBS Switzerland AG                                                                                                    | 63,636,363.64                                                   
|HSBC Bank plc                                                                                                         | 31,818,181.82                                                   
|HSBC Trinkaus & Burkhardt AG                                                                                          | 31,818,181.82                                                   
|Banco Itaú BBA International, S.A. –

        London Branch                                                           | 21,212,121.21                                                   
|Coöperatieve Rabobank U.A., formerly known as

        Coöperatieve Centrale Raiffeisen-

        Boerenleenbank B.A. | 21,212,121.21                                                   
|CA Indosuez (Switzerland) SA, formerly known as

        Crédit Agricole (Suisse) SA                                  | 21,212,121.21                                                   
|Standard Chartered Bank                                                                                               | 21,212,121.21                                                   
|The Bank of New York Mellon                                                                                           | 21,212,121.21                                                   
|The Bank of Tokyo-Mitsubishi UFJ, Ltd.                                                                                | 21,212,121.21                                                   
|Total                                                                                                                 | 1,000,000,000.00                                                





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