FACTBOX-South Korea's forex intervention over past year

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Aug 4 (Reuters) - The South Korean authorities have sold almost $25 billion in the currency markets over the past four months to prop up the won and fight imported inflation, dealers estimate.

South Korea has removed almost all currency controls since the 1997-98 Asia financial crisis but it has frequently intervened in the market, sometimes by issuing warnings, sometimes by directly trading currencies.

Dollar-selling intervention in recent months marks a shift in its policy stance from that of the past 10 years, when it was determined to ensure the won KRW= KRW=KFTC did not rise too fast against the dollar because a strong won hurts exports.

The shift in policy came as inflation rose to its highest in nearly a decade in June due to the rising cost of importing energy and raw materials.

Following are key dates in the past year when dealers have reported the authorities buying or selling dollars against the won, or when policy makers issued remarks aimed at influencing the exchange rate, as compiled by Reuters:

July 31, 2008 - Won rises, authorities seen selling some $1 billion.

July 11-28 - Authorities seen selling a small amount of dollars in at least 11 sessions, whenever the won weakens sharply

July 10, 2008 - Won rises slightly, authorities seen selling a small amount of dollars. One-month won offshore forward contracts rise overnight and intervention cited.