RE: Got my non-answer from IR"The increase on the number of outstanding GDSs was part of a natural expansion, mostly due to the interest of Canadian investors in Oil & Gas Companies. "
https://thismatter.com/money/stocks/global-depositary-receipts.htm
Depositary receipts can be created or canceled depending on supply and demand.
When shares are created, more corporate stock of the issuer is purchased and placed in the custodian bank in the account of the depositary bank, which then issues new GDRs based on the newly acquired shares.
When shares are canceled, the investor turns in the shares to the depositary bank, which then cancels the GDRs and instructs the custodian bank to transfer the shares to the GDR investor.
The ability to create or cancel depositary shares keeps the depositary share price in line with the corporate stock price, since any differences will be eliminated through arbitrage.