Rein has been active in the financial world since 1980.
He started as a Foreign Exchange administration employee at Albert de Bary Bankiers & Co.
In 1985 Rein switched to Schamhart Independent Floorbrokers. This was the largest independent order execution company on the Options Exchange.
From 1995 to 2004 Rein worked as a stockbroker and advisor at SNS Securities and after that he worked successively at AFS Capital Management, Indexus Group and Boer & Olij Securities.
Rein is DSI registered as Sr Investment Advisor and since March 2020 affiliated with Noesis B.V.