Ahead of a G-20 meeting in Buenos Aires Nov. 30, the secretary-general of the OECD has stepped up pressure on Israeli Prime Minister Benjamin Netanyahu and Finance Minister Moshe Kahlon to share taxpayer data with other tax agencies or face being blacklisted.

In Nov. 26 letters, copies of which were obtained by Bloomberg Tax, Angel Gurría warned that Israel has so far failed to implement the Automatic Exchange of Financial Account Information (AEOI) standard adopted by the OECD and...