THORNBURG INVESTMENT TRUST TWENTY-SIXTH AMENDMENT AND SUPPLEMENT TO AGREEMENT AND DECLARATION OF TRUST

Exhibit (a)(25)

XXXXXXXXX INVESTMENT TRUST

TWENTY-SIXTH AMENDMENT AND SUPPLEMENT TO

AGREEMENT AND DECLARATION OF TRUST

THIS TWENTY-SIXTH AMENDMENT AND SUPPLEMENT is made by Xxxxxxx Xxxxxxxxx, Xxxxx X. Xxxx, Xxxxx X. Xxxxx, Xxxxx Xxxxxxx, Xxxxx X. Xxxxx, Xxxxx X. XxXxxxx, Xxxx X. Xxx Xxxxx and Xxxxx X. Xxxxxxxxx (the “Trustees”).

The Trust was formed on June 3, 1987 by an Agreement and Declaration of Trust - Limited Term Trust dated June 3, 1987. The Trustees created a series, Xxxxxxxxx Low Duration Bond Fund, by the execution of a Twenty-Fifth Amendment and Supplement to Agreement and Declaration of Trust, as of September 16, 2013. Section 11.7 of the Agreement and Declaration of Trust permits the Trustees to make certain amendments to the Agreement and Declaration of Trust.

Accordingly, by execution of this Amendment and Supplement, the Trustees change the name of the described series to “Xxxxxxxxx Low Duration Income Fund.”

The Trustees effect this amendment as of December 18, 2013, and direct the Trust’s president to file this Amendment and Supplement in the appropriate governmental offices.

/s/ Xxxxxxx Xxxxxxxxx

Xxxxxxx Xxxxxxxxx

/s/ Xxxxx X. Xxxx

Xxxxx X. Xxxx

/s/ Xxxxx X. Xxxxx

Xxxxx X. Xxxxx

/s/ Xxxxx Xxxxxxx

Xxxxx Xxxxxxx

/s/ Xxxxx X. Xxxxx

Xxxxx X. Xxxxx

/s/ Xxxxx X. XxXxxxx

Xxxxx X. XxXxxxx

/s/ Xxxx X. Xxx Xxxxx

Xxxx X. Xxx Xxxxx

/s/ Xxxxx X. Xxxxxxxxx

Xxxxx X. Xxxxxxxxx

Xxxxxxxxx Investment Trust Twenty-Sixth Amendment and Supplement to Agreement and Declaration of Trust Page 1 of 1