LONDON (AFX) – Shares in BHP Billiton PLC outperformed the wider market in early trade, benefiting from its defensive profile and as analysts at Merrill Lynch said the group’s oil assets have been undervalued by the market, dealers said. Yesterday, at 9.40 am, BHP’s shares were 1-1/4 pence higher at 371-1/2 pence, while the FTSE…