Mutual fund prices precision

[Colin Law]

On 3 August 2015 at 22:31, AC <gnucash at acarver.net> wrote:
>> ..
> As an example, a purchase of 136.742 shares (same precision as the
> statement) for a total price of $650.89 (also same precision) and the
> price per share is 4.759 on the statement and 4.75999 in GC.  The
> statement lists prices per share to three decimals.  There is probably
> internal rounding on their system that I can not see because no
> statement or other record shows more than three decimals of price.

Interestingly neither your bank nor GC seem to have correctly rounded
it, both have truncated.  If you get your calculator out and work out
650.89/136.742 you will see the answer is 4.7599895959 (to that
precision).  So to three decimal places the correct rounded figure is
4.760 and to five decimal places it is 4.76000.

Colin


>
> I don't have the paper statements in front of me at the moment but
> there's another example I can show where a rounding is happening, too
> (the above looks like a truncation) where GC's value is lower than the
> statement value.
>
> I do have another which is an initial conversion (sell off an old fund
> and buy into a new one at one-for-one) which the shares are 429.545,
> total buy-in is 429.55 and the price works out to 1.00001.
>
> I'll just live with the price weirdness unless I can somehow get the
> internal totals to have more significant figures.