CNBC :- Clearing firm Ronin Capital unable to meet capital requirements at CME: Sources
https://www.cnbc.com/2020/03/20/clearing-firm-ronin-capital-unable-to-meet-capital-requirements-at-cme-sources.html

The move forced the exchange to step in and invoke its emergency protocols to auction off the portfolios.

and

Additional sources said Ronin’s problems stemmed from positions in futures tied to the CBOE Volatility Index, or the security that tracks market volatility.

I actually applied for a prop-trading position there about a year or so ago, before I started to really believe in myself and my abilities. I wonder what the positions in the VIX they had on were.