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. So long as you hold the shares up to and including that day, you'll get your money.

We have a small number of companies from the FTSE 100 and FTSE 250 reaching their crucial dates next week. Here are three that will go ex-dividend next Wednesday, May 29.

AMEC (LSE: AMEC)
AMEC, the provider of engineering and other services to a number of sectors including the oil and gas sector, released good-looking full-year results in February. Reported revenue gained 28% to £4.2 billion, with underlying revenue up 21%. And with earnings per share up 14% and operating cash flow up 16%, the firm was able to lift its full-year dividend by 20% to 36.5 pence per share.

The payment comprises an earlier interim dividend of 11.7 pence per share, with a final contribution of 24.8 pence -- and the date for that final portion is May 29. AMEC's dividend yield is not especially high, at 3.5% on the current share price of 1,056 pence, but it is well covered, and the firm has been making reliably increasing annual payouts.

Spectris (SXS)
Electronic instruments and controls specialist Spectris proposed a final dividend of 25.5 pence per share at the time of its annual results in February, taking its total payment for the year to 39 pence per share for a rise of 16%. On the latest share price of 2,109 pence, that provides a yield of 1.8% -- not massively high, but the dividend has been rising nicely over the past few years.

This year's dividend was made possible by an 11% rise in sales to £1.23 billion, adjusted pre-tax profit up 13% to £217 million, and an 11% boost in adjusted EPS to 137.5 pence.

Marston's (MARS 0.73%)
The last of our trio this week is Marston's, the pub manager and brewer, which will go ex-dividend with respect to an interim payment of 2.3 pence per share. Announced with interim results last week, that's a 4.5% increase on the first-half payout a year ago and comes despite underlying pre-tax profit falling 18% to £27.6 million and underlying EPS dropping 19% to 3.8 pence per share. Still, the firm did express confidence in hitting its full-year targets.

If the same increase is repeated for the final dividend, we'd see a payment of near 6.4 pence per share for a yield of 4.2% on the latest 154 pence price -- and that's with the share price having soared by 55% over the past 12 months.

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