Rating activity slowed last week but positive rating actions continued to outnumber negative ones, in line with the trend seen since the start of June. There were two defaults last week, both by U.S. issuers—a plastic packaging manufacturer (Valcour Packaging LLC) and a health care company (Vyaire Medical Inc.). Two new risky credits were added—Upstream Newco, Inc. and Vertex Energy, Inc.—both U.S. issuers, from the health care and oil and gas sectors, respectively. Seventy percent of additions to our risky credits list so far this year have been U.S.-based issuers