Forward Calendar - U.S. corporate bond new issues

May 20 (Reuters) - The following are lists of upcoming high-grade and high-yield corporate bond offerings in the United States. The information was gathered from Thomson Reuters U.S. new issues team, and other market sources: *Denotes 144a private placement debt offering. HIGH-GRADE BOND SALES EXPECTED FOR THE WEEK OF 5/20/2013 COMPANY AMT MAT/DEBT RTGS MGRS PRICED CF Industries $TBA 10-yr Baa2/BBB-/BBB GS/MS