I have tracked down the ASX 200 Fact sheet which, to me,...

I have tracked down the ASX 200 Fact sheet which, to me, indicates that reviews are made quarterly (but using the previous 6 months data):

"The Index Committee reviews constituents quarterly to
ensure adequate market capitalization and liquidity. Both
market capitalization and liquidity are assessed using
the previous six months�f worth of data. Quarterly review
changes take effect the third Friday of December, March,
June, and September."

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