The Financial Post reports in its Tuesday edition that the twin brothers behind one of the world's biggest pharmaceutical fortunes are cutting their holding in a maker of COVID-19 vaccines as demand for the shot wanes. A Bloomberg dispatch to the Post says that Thomas and Andreas Struengmann disclosed sales of $110-million of Biontech SE shares this year and filed last month to offload almost double that sum in one of the billionaires' biggest selling sprees for the New York-listed stock (all figures U.S.). The brothers, who were seed investors in Biontech, are still the German company's biggest shareholders with a 43-per-cent interest ahead of the upcoming sales. Biontech partnered with Pfizer to develop the first COVID vaccine to be approved by the U.S. Food and Drug Administration. The sales show the brothers, worth over $23-billion, are increasingly realizing the gains they made from their early bet on Biontech, which saw its share price boom to record highs during the pandemic. The company's stock has tumbled since then as demand wanes for the COVID shot, leading it to slash its forecast for this year's vaccine sales by 20 per cent. The brothers provided Biontech with $186-million in seed money in 2008.