I don't know. What I can tell you is that RDS-A comes from the main business that was located in the Netherlands. While RDS-B originates from the shipping and transport portion of the company that was based in the UK/Wales. I'd assume this is the reason, but it's only a guess.

Also just to clear up things with BayouSizzle.

quote:
New York
To make it possible for investors in the United States to own shares in the company, Royal Dutch Shell worked with an investment bank, The Bank of New York Mellon, to create a special type of financial instrument. It deposited shares of the Class A and Class B stock with the bank, then issued receipts against these as proof that they were there (called American Depository Shares, or ADS). Those ADS were these packaged into new securities called American Depository Receipts (or ADR).

Each ADR represented 2 shares of the underlying Class A or Class B stock. Dividends are paid in United States dollars.
•The Class A ADR trade on the New York Stock Exchange under ticker symbol RDS.A.
•The Class B ADR trade on the New York Stock Exchange under ticker symbol RDS.B

Edit: Also of note:

quote:
How the Royal Dutch Shell Scrip Dividend Program Works

If the Class A ADR look like a better deal at any given moment, you can get around the Dutch withholding tax by signing up for the Scrip dividend program. Basically, Royal Dutch Shell will agree not to send you any cash, and instead, deposit additional shares of the Class A ADR as a stock dividend into your account. This will exempt you from the 15% Dutch withholding tax. The bad news is, the IRS will still want its 15% dividend tax in April, which is unfortunate because most of the time, stock dividends are tax-deferred. The reason the Scrip dividends are taxes is because you had the option of getting cash if you wanted it, which is enough for the tax man to argue that it was actual income rather than a deferred capital gain.

(For some investors, in some countries around the world, you can use the Scrip dividend program to defer taxes on your Royal Dutch Shell dividends for years when held in a regular taxable brokerage account; even decades. Were us Americans only so lucky.)

Still, you could use this as a mechanism to take advantage of a rare market dislocation in a tax-deferred account, such as an IRA. If you suddenly woke up to a world where the Class A shares were trading at a decided disadvantage to the Class B shares, you could buy the Class A shares in your IRA, sign up for the Scrip dividend program, then get the higher yield in this hypothetical alternate reality without paying any taxes to the Dutch or U.S. governments; instead of dividends, you’d see fresh, newly minted shares of the Class A ADR deposited into your account. If you ever wanted to stop reinvesting the dividends, you could just sell the Class A ADR and swap them into Class B ADR, which would have no tax consequences because you were doing it in a retirement fund.

This post was edited on 1/16/16 at 8:58 am