JPMorgan has hired Citigroup's Matt Cherwin to head its asset-backed securities trading group in New York, which will include synthetics and secondary CDOs. Cherwin is on gardening leave and could not be reached. Brian Marchiony, JPMorgan spokesman, said he will report to Bill King and Christine Cole, co-heads of JPMorgan's securitized products business, who were unavailable for comment. Joseph Christinat, Citi spokesman, did not return a phone call.