here'a a copy/paste of how Pimco distributes dividends
Q: Is a fund’s share price affected when a distribution is paid?
A: Both distributions of dividends and capital gains will reduce the fund’s net asset value
per share (NAV) by the amount of the distribution on the ex-dividend date.
Because the fund’s NAV may also be impacted by
market activity or movement on the ex-dividend date, the total change in a fund’s NAV
may be more or less than the dividend.
Q: What are supplemental dividends?
A: Supplemental dividends are additional ordinary income that must
be paid out by a fund due to tax rules. For PIMCO funds, supplemental
dividends are largely the result of currency gains, which are not
included in book income or in the daily dividend for our daily accrue/
monthly paying funds. Currency gains are accounted for as income for
income tax purposes, and when certain scenarios occur, the additional
amounts are paid out as supplemental dividends. Because we are not
able to perform the necessary calculations until year-end that allow us
to determine whether a supplemental dividend is required, we do not
communicate estimated amounts until we are certain.
It says "largely the result of currency gains, which are not included in book income." This suggests suplemental dividends are largely paid from unrecognized gains not included in book income, and, I assume not included in the calculation of NAV.
The supplemental dividend in December, 2011 was 6.5 cents and the NAV moved 2 cents. I think it worked differently last year. I feel that if the currency gains are not recorded to income, the ditribution would not be subtracted from the market NAV.
Date Open High Low Close Volume Adj Close*
Dec 28, 2011 10.83 10.83 10.83 10.83 0 10.49
Dec 28, 2011 0.065 Dividend
Dec 27, 2011 10.85 10.85 10.85 10.85 0 10.44