The tumbling yields on euro-denominated debt is crimping demand and leading some borrowers to issue in dollars.

Among the borrowers turning to dollar issuance are eurozone supranational and state-backed agencies, which in March raised $22 billion of debt denominated in dollars - the most in more than four years and almost double what they raised in euros, according to data provider Dealogic. It was the first month since October 2010 that this type of borrower raised more funds in dollars than in euros.