Greece’s four biggest banks, which suffered severe losses when they were shuttered this summer as the country veered toward economic collapse, must raise nearly $16 billion in new money to withstand any new crisis, the European Central Bank said on Saturday.

The central bank’s assessment was eagerly awaited by the financial world as a crucial step in determining how much money the Greek banks would require to achieve stability as the country tries to claw its way out of its deep economic hole.

One of the biggest problems for the Greek banks is the high number of loans to businesses and consumers that are at risk of not being repaid — nearly 50 percent of the loans outstanding.

The central bank report put a figure — 14.4 billion euros, or about $15.9 billion — on what it would take to address the bad-loan problem and enable the Greek banks to operate once again as fully functioning lenders. Without healthy banks to provide the lending and liquidity an economy requires, Greece would struggle to resume economic growth.