It’s because they’re using European mathematics. You wouldn’t understand if you’re American.

In reality the article is attempting to account for a capital gain pnl accounting for taxes.

price of gold dropped from $5500 to $4600 in the last few weeks then came back. all is possible

Usually that's how you want your selling and buying combos to be...

From the annual report, it looks like the headline number (XXB gain) is just because it's realized capital gain (which due to their reporting requirement appears in their annual report, unlike unrealized gains).

They have ~same amount of gold between both years and it doesn't look like they took extra market risk.