numbers STOCKH function for historical stock prices The function STOCK("WTR") in numbers 6.2.1 works well, it returns as a value today 51.94US$ and it returns also an overview window.

However, when I use STOCKH("WTR",0,"29 Mar 2020") it returns "The requested historical date is invalid or is in the future".

a) I am assuming the abbreviation "WTR" is correct, as it works with the STOCK function. Is there a list of available options? -- I guess it is powered by yahoo, and there is a "WTR" in yahoo

b) Would "WTR.N" specify the stock exchange in New York City?

c) I've tried various flavours of the date string. However, it either tells me it's an invalid string or the above error message.

(d) for other stocks this works well, e.g., for "APC.F"
The chart data for WTR on Yahoo Finance – which is indeed the data source – stops at February 24th, 2020.

So, there indeed seems to be no historical data for WTR after this date.

If you use "Feb 24 2020" as the date, Numbers shows the closing price perfectly fine.

Edit:

(a) Please note that STOCK("WTR") returns the price from January 30th, 2020.

(d) As a sidenote, STOCKH("APC.F",0,"29 Mar 2020") returns an error for me, which is correct as there is no trading in Frankfurt on weekends.

The function browser description recommends error handling by using IFERROR in front of the STOCKH function.