They offer an indirect source for the one explicit claim made in the article: 20% of the price increases in London due to laundering. It's not linked, and I was

They offer an indirect source for the one explicit claim made in the article: 20% of the price increases in London due to laundering. It's not linked, and I wasn't able to find an article online, but the claim is credited to "Christoph Trautvetter of Netzwerk Steuergerechtigkeit" Aside from that concrete claim, they offer a plausible explanation for why something that may make up a small proportion of sales could cause an outsized increase in prices. And they do draw comparisons to known cases in stock markets. So I think it's still an interesting article.