German banks hold $28 billion euros or $37 billion in Greek bonds according to Barclays Capital using IMF data. This debt is now rated as junk by Standard and Poor's since last week. Just one bank, Hypo Real Estate, now owned by the German government after a bailout has $10.5 billion of Greek bonds. This gives a new twist to what is happening in Greece, with Germany involved through the support its own banks would need if Greece defaulted and these bonds become worthless. Total debt holdings of Portugal, Italy, Ireland, Greece and Spain for example at Hypo Real Estate is $52 billion. France is also heavily involved through its banks. It has $67 billion in holdings, including $9 billion held by the Bank of France, according to Barclays. According to BIS data American banks hold $16.6 billion in Greek debt. Even the healthy large Spanish banks like Santander have their problems, with Santander having $64 billion of assets in Portugal, according to analysts at Nomura in London. In Spain most of the bad debt problems are concentrated in the midsize banks, but if Portugal were to take a hit then the large banks would be affected adversely....