Oil producers such as Afren and Premier Oil, and energy services firms Wood Group, Hunting and Petrofac, were all falling sharply on Monday as the price of oil continued to sink. Brent crude dropped below $55 a barrel (bbl) for the first time since May 2009.Afren was also continuing to decline after reaching a settlement last week with its former chief executive and chief operating office, who paid £13m back to the firm after they were fired over unauthorised payments.Hikma Pharmaceuticals received an upgrade to a 'buy' rating from equity analysts at Jefferies Group in a research note sent to investors on Monday. JP Morgan also lifted its price target on Hikma shares by 18.4% and maintained an 'overweight' rating.Poundland Group was on the rise after its chief executive Jim McCarthy was reported as saying there is potential to open 400 of its Dealz stores in Spain.Man Group rose after the fund manager was added to the 'buy' list by The Share Centre. Investment research analyst Helal Miah said: "These funds have struggled to retain investor confidence in subsequent years and experienced significant fund outflows. However, we believe the long awaited turnaround in the fortunes of this business has begun and the shares have been creeping upwards on the more positive sentiment." FTSE 250 - RisersHikma Pharmaceuticals (HIK) 2,097.00p +5.80%Man Group (EMG) 166.10p +3.23%Pace (PIC) 350.80p +2.99%Nostrum Oil & Gas (NOG) 452.00p +2.73%Bank of Georgia Holdings (BGEO) 2,162.00p +2.61%Ted Baker (TED) 2,257.00p +2.59%Poundland Group (PLND) 329.90p +2.52%RPC Group (RPC) 515.50p +2.49%BTG (BTG) 819.00p +1.87%Hellermanntyton Group (HTY) 322.10p +1.87%FTSE 250 - FallersAfren (AFR) 42.80p -6.16%Oxford Instruments (OXIG) 1,214.00p -5.16%Evraz (EVR) 144.80p -4.74%Premier Oil (PMO) 157.30p -4.49%Wood Group (John) (WG.) 588.00p -4.47%Hunting (HTG) 503.50p -3.91%Petrofac Ltd. (PFC) 684.00p -3.80%Drax Group (DRX) 437.40p -3.76%Vedanta Resources (VED) 558.50p -3.46%Ladbrokes (LAD) 109.10p -3.11%