More than eight years after the collapse of the global financial system, Europe's banks are still struggling — and things may get worse.

The latest threat to euro zone banks comes from Italy, where the world's oldest bank, Monte dei Paschi, is running out of cash. On Wednesday, it disclosed that without fresh capital, it will be insolvent within four months. Previously, it was saying it had enough cash to last 11 months. The bank was founded in 1472.

Italian officials are expected to meet Friday to formally approve a 5 billion euro ($5.2 billion) government rescue of the world's oldest bank, just days after it failed to raise enough private cash to stay afloat.

But with Italy's banks mired in bad loans and the country's economy going nowhere, the move may prove to be too little, too late.