UPDATE 1-ETF Securities Platinum ETC holdings drop 30 pct

(Updates with background, details)

LONDON, Aug 18 (Reuters) - ETF Securities said on Monday the amount of platinum it holds to back its Physical Platinum (PHPT.L) exchange-traded commodity fell 30 percent in the week to Aug 17.

The ETC is now backed by 218,165 ounces of metal, its lowest point since February 5 and some 46 percent below the all-time high of 407,000 ounces it hit in early July.

Platinum prices have dipped sharply in recent weeks as investors worry about the outlook for the car industry, a major consumer of the metal, amid a gloomy global economic outlook.

Spot platinum XPT= is currently trading 25 percent below its price a month ago.

The company's Physical Palladium ETC (PHPD.L) saw an outflow of 10 percent, or just over 25,000 ounces, in the same week, the company added.

Meanwhile its Physical Gold ETC holdings ticked up, climbing 4 percent to 1.800 mln ounces from 1.728 mln the week before.

(Reporting by Jan Harvey; Editing by Peter Blackburn)