Alvaro Ballesteros, a high yield credit-default swap trader at WestLB in London, has left the firm and market officials have connected him with a similar role at BNP Paribas. Ballesteros, who is on gardening leave and could not be reached for comment, reported to Ian Claisse, global head of credit trading, who did not return messages. Sarah-Jane Purvis, spokeswoman in London, confirmed Ballesteros' departure after two years at the firm, declining comment on a replacement. Ruth Lavelle, spokeswoman for BNP in London, did not return calls by press time.