Alfred Léonard Loewenstein (11 March 1877 – 4 July 1928) was a Belgian financier. At his peak in the 1920s, Loewenstein was worth around £12 million in the currency of the time (equivalent to £ million in ), making him the third-richest person in the world at the time. His wealth came from investments in electric power and artificial silk businesses when those industries were in their infancy. Loewenstein is remembered today for his mysterious disappearance and death in 1928. Early life and business career Alfred Loewenstein was born to Bernard Loewenstein, a German-Jewish banker in Brussels, Belgium, who converted to Catholicism. Alfred established his own banking concern, and was a wealthy man by 1914. Loewenstein offered his government in exile US$50 million, interest-free, to stabilize the Belgian currency in return for the right to print Belgian francs. The offer was refused. At war's end, he maintained a residence in England where he ran an investment business that made him one of Europe's most powerful financiers. He partnered with the investment house of Canadian-born Sir James Dunn in several business ventures, the duo emerging with more than £1,000,000 profit from their 1920s investment in British Celanese alone. Loewenstein was an owner of a successful stable of thoroughbred steeplechase race horses. His horses won the 1926 and 1928 runnings of the Grand Steeple-Chase de Paris. Business successes Loewenstein made an enormous fortune providing electric power facilities for developing countries worldwide through his Belgian-based company, Société Internationale d'Énergie Hydro-Électrique (SIDRO). By the mid-1920s, Loewenstein's reputation was such that he was consulted by heads of state from around the globe. The British government made Loewenstein a Companion of The Most Honourable Order of the Bath. In 1926, Loewenstein established "International Holdings and Investments Limited", which raised huge amounts of capital from wealthy investors wishing to get aboard his bandwagon of success. However, he was rebuffed in his attempt to take over a Canadian company called Barcelona Traction, Light, and Power, a huge operation building infrastructure in Brazil. In 1926, he bought a sumptuous house in Biarritz, in the French Basque Country, with a view on the Bay of Biscay and the Atlantic Ocean. In 2019, Sotheby's International Realty shows the house. Alleged drug deal with Arnold Rothstein The writer Johann Hari has alleged that shortly before his death, Loewenstein had made a deal with American crime boss Arnold Rothstein to supply opiates into