The company extended the bond's term to February 18, 2029, and cut its annual coupon rate to 4% from 5%, Maritsa 3 said in a bourse filing.
The changes were approved at a general meeting of bondholders on November 9.
The bond was issued in 2013, bourse data show.
Last week, Maritsa 3 said it significantly cut its standalone net loss to 9.1 million levs in the first nine months of 2023 from 66.7 million levs a year earlier as a result of a sharp drop in expenses.
Shares in TPP Maritsa 3 last traded at 134.628 levs on the BaSE market of the Bulgarian Stock Exchange.
(1 euro = 1.95583 levs)