yep, it's a solvency issue. The minute they tried to offload the bonds at a price lower than they paid for them (which seemed like the right thing to do to fix the liquidity issue), they were effectively in a hole and even if they waited 10 years later, would not have been able to cover the deposits.
They NEEDED to raise capital.
Their liabilities > assets.
They were 100% insolvent.
I don't know the answer, but I see both sides. As of today, their liabilities exceed their assets worth, so it does feel like solvency fits.