LONDON -- If you want to be eligible for a dividend payment, or if you're watching for possible share price falls, keeping up with ex-dividend dates can prove beneficial -- as long as you hold the shares up to and including that day, you'll get your money.

We have a handful of FTSE 100 companies reaching the all-important day next week. The following three will go ex-dividend next Wednesday, May 15.

Royal Dutch Shell
Oil giant Royal Dutch Shell (LSE:RDSB) (NYSE:RDS-B), the biggest company in the FTSE 100, released first-quarter figures last week and announced a dividend of $0.45 per share, or 29 pence at today's exchange rate. That's a rise of 5% on the first quarter of 2012, and with Shell's dividends spread evenly over the year, that would suggest a full-year payment of $1.80, or 116 pence per share -- which would provide a yield of 5% on the current share price of 2,312 pence.

In addition to dividends, Shell is returning cash to shareholders via its share buyback programme, and bought up 16 million shares during the quarter for a total of around $500 million.

Wm Morrison
Wm Morrison Supermarkets (LSE:MRW) announced full-year results on 14 March, and will pay a final dividend of 8.31 pence per share. That will take the total for the year to 11.8 pence, up 10% in line with the firms policy of a minimum 10% increase in each of the three years to 2014. The dividend is covered 2.32 times by earnings.

On the year-end share price, that represented a yield of 4.7%, which is historically high by supermarket standards. On the current share price of 295 pence, a 10% dividend rise to 13 pence per share for 2014 would provide a yield of 4.4%, as the shares have gained 17.5% since the 31 January year-end.

G4S
It's ex-dividend time for G4S (LSE:GFS) next Wednesday, too, after March's full-year results revealed a 5.54 pence final dividend. Added to an interim payment of of 3.42 pence per share, that lifted the security firm's total for the year by 5% to 8.96 pence. The firm also said it plans to continue dividend increases "broadly in line with normalised adjusted earnings."

On the year-end, price, that was a yield of 3.5%. And though the shares powered upward since then, this week's slump, led by disappointing first-quarter results, has taken them back to 261 pence. That leaves the yield still at around 3.4%, and indicates a possible 3.7% for the year to December 2013.

Finally, dividends like these can add nicely to your investment returns -- they can be spent or reinvested according to your needs. Whether investing for income or growth, good old cash is always welcome.

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Alan Oscroft has no position in any stocks mentioned. The Motley Fool has no position in any of the stocks mentioned. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.