Portfolio Duration is out of the winner Shemya (Dansili) and is a half-sister to Cormorant (Kingman), winner of the Gr.3 Derby Trial Stakes in Ireland. They are Shemya's only winners so far.

Second dam Shemima (Dalakhani) won the Gr.3 Prix Allez France and the Gr.3 Prix de Lutece and had four other winners. She is also the second dam of No Show Sammy Jo (Lope De Vega), a Grade 3 winner in the US.

Third dam Shemaka (Nishapour) won the Gr.1 Prix de Diane and bred six winners. Among them are Shemala (Danehill), winner of the Listed Prix Madame Jean Couturie and dam of Shemiyla, who took the Gr.3 Prix Allez France, Shemaya (Darshaan), a Listed winner and dam of Shamkiyr, second in the Gr.1 Prix du Jockey Club, and the Listed-placed Shediyama (Red Ransom).

Shemya has an unnamed two-year-old colt by Palace Pier and a yearling colt by Modern Games, and was covered by Chaldean in 2025.