[5] Speelman began his career in the art business at the Dutch firm Duits where he was employed to help form a photographic library.
A strong linguist he was able to form a profitable association with the Dutch dealer Nathan Katz, who spoke no English, and he often collaborated with Colin Agnew and Claude Partridge.
In 2017 The Oyster Meal, by Jacob Ochtervelt, which Speelman had sold to collector Harold Samuel, was discovered to have been looted by Nazis from Dr Smidt van Gelder, director of the children’s hospital in Arnhemr.
[6] Also in 2017 a settlement was reached concerning a painting by Michele Marieschi between the family of an Austrian Jewish art collector who had been looted by the Gestapo and a foundation in possession of the work.
[7] On October 7, 2021, "View of Beverwijk" by Salomon van Ruysdael was deaccessioned by the Museum of Fine Arts, Boston in order to restitute it to the heirs of Ferenc Chorin, who had been looted by the Nazis.