ADRs represent the right to receive securities of foreign issuers deposited in a domestic bank or a correspondent bank. ADRs are an alternative to purchasing the underlying securities in their national markets and currencies. For many foreign securities, U.S. dollar-denominated ADRs, which are traded in the United States on exchanges or over-the-counter (“OTC”), are issued by domestic banks. In general, there is a large, liquid market in the United States for many ADRs. Investments in ADRs have certain advantages over direct investment in the underlying foreign securities because: (i) ADRs are U.S. dollar-denominated investments that are easily transferable and for which market quotations are readily available, and (ii) issuers whose securities are represented by ADRs are generally subject to auditing, accounting and financial reporting standards similar to those applied to domestic issuers. ADRs do not eliminate all risk inherent in investing in the securities of foreign issuers. By investing in ADRs rather than directly in the stock of foreign issuers outside the U.S., however, the Funds may avoid certain risks related to investing in foreign securities on non-U.S. markets.
There's a lot of ins and outs which can get confusing in arbitrage trading. We won't go into the technicals of why futures contracts trade at a premium to spot price. You can read a full explanation here. If it's not of interest to you, all you need to know is that there's a tendency, the further out in time the futures contract expires, for the premium to spot to be higher and higher in nominal percentage terms.