[GNC] Stock "split" exchanging shares of different currencies?

[Jim DeLaHunt]

I did a curious stock transaction, and I'm having trouble when I record 
this transaction in GnuCash 3.10.

I bought some shares of a fund, DLR.U, which trades in US Dollar prices 
on the Toronto Stock Exchange. I exchanged those shares for an identical 
quantity of shares in that fund with a different name, DLR, which trades 
in Canadian Dollar prices on the Toronto Stock Exchange. The purpose was 
to exchange US dollars for Canadian dollars at lower cost, via the 
so-called Norbert's Gambit 
<https://wealthsavvy.ca/norberts-gambit-questrade/>.

The basic idea of Norbert's Gambit is that if the same security trades 
in one market in one currency, and also in a second market in a second 
currency, then the ratio between the two prices will always be close to 
the market currency exchange rate. If the prices ever diverge, this 
becomes an arbitrage opportunity: buy shares on the first market in the 
first currency, sell the same quantity shares on the second market for 
the second currency, convert funds back to the first currency in the 
conventional foreign exchange market, and profit. The net number of 
shares at the end of the transaction is zero. The DLR/DLR.U fund was 
created to facilitate Norbert's Gambit, but the same technique is 
possible with any stock which is traded in multiple liquid markets in 
multiple currencies.

I had no trouble recording my purchase of DLR.U, in US dollars, in the 
US Dollar-denominated brokerage account. I just followed the 
instructions in the GnuCash Guide, 9.5. 
<https://gnucash.org/viewdoc.phtml?rev=3&lang=C&doc=guide>/Buying Shares 
<https://gnucash.org/viewdoc.phtml?rev=3&lang=C&doc=guide>/.

The problem was recording the moving of the DLR.U shares to DLR, in 
Canadian dollars, in a Canadian Dollar-denominated brokerage account. I 
started off by following the instructions for a stock split in the 
GnuCash Guide, 9.10.2. /Moderately Complex Stock Merger/ 
<https://gnucash.org/viewdoc.phtml?rev=3&lang=C&doc=guide>. I took the 
example of SBC shares turning into ATT shares plus cash, and changed it 
to have DLR.U shares exchange for an equal number of DLR shares.

The transaction I entered was this (simplified a bit from my actual 
numbers):

*Account* 	*Shares* 	*Price* 	*Buy* 	*Sell*
Brokerage CAD:ETF:DLR 	200 	14.00 	2,800.00 	
Brokerage USD:ETF:DLR.U 	-200 	10.00 	
	2,000.00

That is, move out 200 shares of the US-dollar DLR.UR, at the share price 
at which I bought them, and bring in 200 shares of the Canadian-dollar 
DLR, at the share prices they were at when I bought the DLR.U.  That's 
pretty much what the real-world journal transfer of shares in my 
brokerage account was like.

I expected that GnuCash would add in TRADING:FUND splits to balance the 
quantity of DLR and DLR.U shares in the transaction. I expected to see:

*Account* 	*Shares* 	*Price* 	*Buy* 	*Sell*
Brokerage CAD:ETF:DLR 	200 	14.00 	2,800.00 	
Trading:FUND:DLR.U 	200
	10.00
	2,000.00
	
Brokerage USD:ETF:DLR.U 	-200 	10.00 	
	2,000.00
Trading:FUND:DLR 	-200 	14.00 	
	2,800.00

What I got was that, plus a Trading:CURRENCY:CAD split that was not 
motivated by anything, and then an Imbalance-CAD split to balance the 
Trading:CURRENCY:CAD split:

*Account* 	*Shares* 	*Price* 	*Buy* 	*Sell*
Brokerage CAD:ETF:DLR 	200 	14.00 	2,800.00 	
Trading:FUND:DLR.U 	200 	10.00 	2,000.00 	
Trading:CURRENCY:CAD 	
	
	800.00 	
Brokerage USD:ETF:DLR.U 	-200 	10.00 	
	2,000.00
Trading:FUND:DLR 	-200 	14.00 	
	2,800
Imbalance-CAD 	
	
	
	800

I will observe that the Trading:CURRENCY:CAD split amount is exactly the 
difference between the ETF:DLR amount and the FUND:DLR.U amount, if you 
disregard that one is in CAD and the other is in USD. It makes me 
suspicious that GnuCash doesn't know how to handle a multi-currency 
stock swap transaction.

Should there be a way to record this transaction correctly in GnuCash? 
If so, what do I do?

Or, is this a limitation in GnuCash? If so, I should file a bug about it.

I am running GnuCash 3.10 on macOS 10.16.5. I have trading accounts enabled.

I have not found anything about Norbert's Gambit or this kind of 
multi-currency stock transaction in the documentation, the mailing list 
archives, the bug database, or the wiki.

Best regards,
       —Jim DeLaHunt, software engineer, Vancouver, Canada