1/ By far, the biggest Ponzi scheme I've discovered until now was the diamonds one. In 2014, two years before other media and 3 years before prosecutors, I wrote stories about physical diamonds sold by 2 brokers through banks to tens of thousands of Italian investors.

2 / Diamonds were sold at constantly rising prices in a sort of linear progression, which wasn't related to real market prices. The prices were produced by the two brokers themselves, Intermarket Diamond Business (Idb) and Diamond Private Investment (Dpi), then published monthly

3/They published monthly table of their prices in markets pages on my newspaper, Il Sole 24 Ore, Italy's highest-selling financial daily. Then the 2 diamonds brokers cut the price tables from the pages and presented them to the public as "Il Sole 24 Ore records" but they weren't

4 / People were lured into the scheme with the promise of constantly revaluating physical luxury assets, easy to be hidden (a lot of diamonds were sold to tax evaders and probably gangsters). For just connecting their clients to the 2 brokers, banks earned 15-20% fees.

5 / The business throve thanks to a hole in Italy's financial regulations: diamonds weren't overseen neither by Bank authority Bank of Italy nor financial authority Consob. In two decades, the 2 brokers sold diamonds for 2/3 billion € proceeds.