Royal Dutch Shell has two classes of share listed on the London stock exchange. One has the ticker "RDSB", and you'll find this ticker quoted in articles here on the Motley Fool. The other class of share has the ticker "RDSA".
The shares carry identical economic rights, but their cash dividends come with different tax implications. The A shares have a Dutch source for tax purposes and are subject to Dutch dividend withholding tax (15%), whereas the B shares have a UK source for tax purposes and are not subject to any withholding tax. Also, cash dividends on the A shares are paid, by default, in euros; cash dividends on the B shares are paid, by default, in pounds sterling.
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