Three of Greece’s leading lenders, National Bank, Alpha and Eurobank, are among the most vulnerable European banks to a downturn in Central and Eastern European markets (CEE), according to a note prepared by Citigroup. Shares in Greek banks, which have expanded into countries such as Bulgaria, Romania and Turkey in recent years, have fallen 70 percent in the last six months, on concerns that deteriorating conditions in CEE markets will harm the quality of their loan book. In addition to the evident economic slowdown, banking systems are typically very volatile across these regions, Citigroup said in a report dated February 20. Data from past crises in 75 emerging markets from around the world show that non-performing loans (NPLs) reached 34 percent of the loan book – half of which would be lost. «For many banks in Europe, a repeat of this could prove deeply damaging,» Citigroup said. NPLs are loans on which no interest has been paid by the borrower for more than 90 days.