Jon Matonis will write the story with a headline something like this "$1M+ USD bitcoin ponzi scheme collapses"
Last week, BS&T paid out 26,000 BTC in interest.
The top tier interest rate is 7%. Some people get less. If we assume everyone got 7%, then that means there is 371,428 BTC invested, but since not everyone gets 7%, the true figure is higher. Also, this doesn't include the people who automatically reinvest their interest. I've no idea what percentage of the interest is automatically reinvested, but let's assume it's none at all.
Even with these assumptions, the least possible amount invested is 371,428 BTC, or $3,298,280 at the current price of $8.88/BTC.