10 Best ADR Stocks to Buy in 2021 Investors in the United States have been steadily pouring money into foreign equities ever since the process was made easier through the introduction of American Depositary Receipt (ADR) in the early part of the twentieth century. According to an estimate by financial expert Arin Ray, the investments into ADRs were increasing at a rate of more than 10% almost a century after they were first introduced, reaching close to $4 trillion by the end of 2010, representing approximately 20% of the total equity holdings in the US. Ray, part of financial services company Celent, cited the high rates of return and a frenzy for diversification as some of the main reasons behind the popularity of ADRs. Since his research was published, the size and trading activity of ADRs on the stock market has grown dramatically. Chinese companies like Alibaba Group Holding Limited (NYSE: BABA), Baidu, Inc. (NASDAQ: BIDU), and NIO Inc. (NYSE: NIO) now represent an increasing chunk of the total ADR-related spending in the US, taking the mantle over from British firms in the past few years.