The Reserve Primary Fund was a large money market mutual fund.
On September 16, 2008, during the Global financial crisis of September–October, 2008, it lowered its share price below $1 ("breaking the buck") because of exposure to Lehman Brothers debt securities. This resulted in demands from investors to return their funds as the financial crisis mounted. Normally, the net asset value of money market funds is kept at $1.
Reserve Management had multiple other funds frozen because of this failure. It has liquidated a few funds, and post periodic updates about plans to liquidate other funds on its website.I had been looking for work for quite some time during my postdoc - I think I knew that the economy was in trouble by that point. I have clear memories of discussing the Reserve Fund failure with my interviewer, who was kind enough to pick me up in his car.
Glad things are somewhat better now than back then.