Lehman went bust because liquidity in the credit markets dried up - i.e they were unable to roll short-term financing to fund longer-dated balance sheet. The markets thought Lehman had big exposure to the US residential and commercial mortgages, hence they couldn't borrow, hence they went bust.
A shame because they weren't actually bankrupt - PWC has now recovered 100% of liabilities with assets to spare.
A shame because they weren't actually bankrupt - PWC has now recovered 100% of liabilities with assets to spare.