France pulls last gold held in US for $15B gain

https://www.mining.com/france-pulls-last-gold-held-in-us-for-15b-gain/

Is anyone here actually reading the article? Yes, they really made a gain of $15B:

> But instead of refining and transporting the gold, it opted to sell the bars and purchase new bullion in Europe. […] Due to rising gold prices, the move helped the bank to generate a capital gain of 13 billion euros ($15 billion),

This doesn't make sense. If they first sold the bars held in the US, then the gold prices rose, then they bought gold in Europe, how the hell did that amount to a capital gain of $15b? How exactly do prices rising over the course of the process lead to these $15b?
Gold is down 10+% since its recent peak. They likely sold then and repurchased later.

Then they made money thanks to gold prices fluctuating, not thanks to gold prices rising?

And how does a 10% market shift lead to gaining $15b, roughly the value of 100 tons of gold, from the sale and re-purchase of 129 tons of gold?

This math ain't mathing.

Other costs? Deviations in the actual figures from the estimates we're using here? 100 is not a million miles away from 129.