LONDON — Brent crude oil fell almost $2 a barrel on Monday to a new five-year low on predictions that oversupply would keep building until next year after OPEC decided not to cut output. “Without OPEC intervention, markets risk becoming unbalanced, with peak oversupply likely in the second quarter of 2015,” Morgan Stanley analyst Adam Longson said. In a report dated Dec. 5, the US investment bank said oil prices could fall as low as $43 a barrel next year. The bank cut its average 2015 Brent base-case outlook by $28 to $70 per barrel, and by $14 to $88 a barrel for 2016. Brent crude for January was down $1.45 at $67.62 a barrel by 1030 GMT, having fallen $1.72 to $67.35 — its lowest since October 2009. US crude was down $1.16 at $64.68 a barrel, after hitting a session low of $64.63. — Reuters