Shareholder yield is the sum of the following:
Dividend yield + Percentage of Shares Repurchased
For example if a company trading at €50 and pays an annual dividend of €1, its dividend yield (DY) is 2%.
If same company had 1,000,000 shares outstanding at beginning of year and 900,000 at end of year, the company's share repurchased yield would be 10% ((1,000,000 – 900,000)/1,000,000).
If you add the two percentages together you get a Shareholder yield of 12%.
Note that the Shareholder Yield can also be negative as Percentage of Shares Repurchased can be negative if shares outstanding increases.