On January 10, 2014, the US and Italy entered into a bilateral agreement for the implementation of FATCA
The Italian agreement is based on the Model 1A treaty and requires Italian financial institutions to report their US account holders to the Italian government, which in turn will report those accounts to the US government. Similarly, US financial institutions are required to report their foreign account holders to the US government, and the US government will communicate this account information to the Italian government.
With the signing of the bilateral agreement with Italy, most of the countries in Western Europe have entered into bilateral agreements. Belgium, Portugal, and Austria are the exceptions so far.