Tullett Prebon Plc, a London-based inter-dealer broker, rehired Shane Burton to oversee its carbon options business after Jerry Vlam, 43, left the firm last month.
Tullett persuaded Burton to return after leaving the company about a year ago, Nigel Szembel, a spokesman at the broker, said in an e-mailed response to questions.
Carbon trading via brokers including Tullett plunged last month to its lowest since at least January 2011, according to the London Energy Brokers’ Association, as banks scaled back buying and selling amid tighter regulation and a glut of permits that pushed prices to a record low in April.
Inter-dealer brokers such as Tullett and ICAP Plc act as a go-between for banks that trade bonds, stocks, currencies, energy and derivatives. Tullett reported a 5.4 percent drop in first-half pretax profit on July 30. Its shares have climbed 35 percent this year, valuing the broker at about 739 million pounds ($1.1 billion).