December 21, 2016 — In the headlong rush to revolutionize modern finance, blockchain enthusiasts are overlooking one potentially costly problem: their applications, built on open-source code, may actually belong to someone else. Recently, some of the biggest names in business, from Goldman Sachs to Bank of America and Mastercard, have quietly patented some of the most promising blockchain technologies for themselves. Through mid-November, the number of patents that companies have obtained or said they’ve applied for has roughly doubled since the start of the year, according to law firm Reed Smith.