Ophir Energy Plc, a U.K. explorer in Africa, fell the most in almost 10 months in London trading after a Tanzanian well showed less natural gas than expected.
The shares plunged 10 percent to close at 522 pence, the biggest one-day decline since Oct. 4.
Ophir found 500 billion to 2 trillion cubic feet of gas resources at the Papa-1 well, it said today in a statement. With partner BG Group Plc, Ophir had targeted 3.1 trillion cubic feet to justify developing a two-unit liquefied natural gas plant, Chief Executive Officer Nick Cooper said in June.
“This is a relatively poor result,” Stuart Joyner, head of oil and gas analysis at Investec Bank Plc, said in an e-mailed report. He downgraded London-based Ophir to hold from buy on July 31.