Some very rich people have eschewed money market funds for muni auction funds for the extra li'l bit of interest.

For half a century, the muni auctions have been as solid as money market funds.

But recently the market dried up. It's completely illiquid. Many billions of hard earned cash (in other words, money that's needed NOW) are sitting there and no one knows what to do to buy that paper so people can get their money back.

The sad part is that this doesn't only effect rich people with brokers who put them into this market in the first place (the brokers themselves never imagined this would happen since this market has been used as a safe haven for decades) but employees at many companies. Apparently, some in management have been parking payroll $$$ in these auctions. So people aren't getting paid.

How much is sitting there without buyers?

Could be $30-50 billion.