NATIXIS OAKMARK FUND

NATIXIS OAKMARK INTERNATIONAL FUND

Supplement dated May 17, 2019, to the Natixis Funds Statement of Additional Information, dated May 1, 2019, as may be revised and supplemented from time to time.

Effective immediately, the subsection entitled “Fund Securities Owned by the Trustees” within the section entitled “Management of the Trusts” is revised as follows:

Dollar Range of Fund Shares1	Kenneth A. Drucker	Edmond J. English2	Richard A. Goglia2	Wendell J. Knox2	Martin T. Meehan2	Maureen B. Mitchell	James P. Palermo2	Erik R. Sirri2	Peter J. Smail	Cynthia L. Walker2
Natixis Oakmark Fund	A	A	E	A	A	A	A	A	A	A
Natixis Oakmark International Fund	A	E	A	A	A	A	A	A	A	A

¹ A. None

B. $1 – 10,000

C. $10,001 – $50,000

D. $50,001 – $100,000

E. over $100,000

² Amounts include economic value of notional investments held through the deferred compensation plan.

LOOMIS SAYLES STRATEGIC ALPHA FUND

GATEWAY EQUITY CALL PREMIUM FUND

GATEWAY FUND

Supplement dated May 17, 2019, to the Natixis Funds Statement of Additional Information, dated May 1, 2019, as may be revised and supplemented from time to time.

Effective immediately, the subsection entitled “Fund Securities Owned by the Trustees” within the section entitled “Management of the Trusts” is revised as follows:

Dollar Range of Fund Shares1	Kenneth A. Drucker	Edmond J. English2	Richard A. Goglia2	Wendell J. Knox2	Martin T. Meehan2	Maureen B. Mitchell	James P. Palermo2	Erik R. Sirri2	Peter J. Smail	Cynthia L. Walker2
Strategic Alpha Fund	A	A	A	A	A	C	A	A	E	A

Interested Trustees

Dollar Range of Fund Shares1	Kevin P. Charleston	David L. Giunta
Equity Call Premium Fund	E	A
Gateway Fund	A	E

¹ A. None

B. $1 – 10,000

C. $10,001 – $50,000

D. $50,001 – $100,000

E. over $100,000

² Amounts include economic value of notional investments held through the deferred compensation plan.