South Sea Company

South Sea Company in 1711 managed to get pretty much all of England, including the royal family, investing in it using shady and illegal tactics, getting the company valued higher than the GDP of England, without actually producing any product. It collapsed and almost destroyed England's economy. When the company collapsed in 1720, it defaulted on £9 million in debts. In today's terms, that is £1,205,000,000. However, this is not a very accurate amount. In real terms, as in how much this would actually be worth in real terms of goods, as in purchasing power, this would be £23,960,000,000.

This is still not the true number either, as this date is far enough back, and so large, that it is not the same percentage of the GDP it is now. For example, if you owned $5 million, but there was only $5.5 million in the whole economy, you would have a much higher relative wealth, and that's the number that really matters in this case.

If we were to make the amount the same percentage of GDP now (with the real/purchasing parity included), that $9 million is the same as £152,700,000,000 now. This is $227,512,311,000 in US dollars. It was a Ponzi scheme on a scale never seen before or since.