Is the method of adjusted close calculation correct at Yahoo?

Discussion in 'Stocks' started by m.runner, Sep 3, 2010.

  1. m.runner

    m.runner

    Is the method of adjusted close calculation correct at Yahoo?

    Example: Adjusted Close Calculations
    http://help.yahoo.com/l/us/yahoo/finance/quotes/quote-12.html

    2/13/03 Close = 46.99
    2/14/03 Close = 48.30
    2/18/03 Split = 2:1
    2/18/03 Close = 24.96
    2/19/03 Cash Dividend = 0.08 (ex-date)
    2/19/03 Close = 24.53

    Split Multiplier = 0.5
    Dividend Multiplier = 1 ∓ (0.08/24.96) = 0.9968

    2/13/03 Adj. Close = 0.5 * 0.9968 * 46.99 = 23.42
    2/14/03 Adj. Close = 0.5 * 0.9968 * 48.30 = 24.07
    2/18/03 Adj. Close = 0.9968 * 24.96 = 24.88
    2/19/03 Adj. Close = 24.53

    But 24.53 / 24.88 - 1 = -0.014067 is not equal to (24.53 + 0.08) / 24.96 - 1 = -0.014022
    Why do they use wrong method?

    I think the pre-dividend data need to be multiplied by 1 / (1 + 0.08 / 24.53 ) in case of dividend distribution.