Nonsense. They would be in violation of Federal Reserve Board policy. https://www.investopedia.com/terms/n/non_marginable_securities.asp https://www.investopedia.com/university/margin/margin1.asp https://finance.zacks.com/buy-penny-stock-margin-11883.html Maybe they are floating the 3-day settlement rule for you on a pseudo-margin-method - TD does as well - but nothing more than that. Granted there are a few exception OTCs that make the Fed Reserve "allow margin" list- but that is NOT the norm.