(ShareCast News) - The FTSE 250 started to climb back on Wednesday to 16,687.19 - up 157.21 points (0.95%)Premier Oil rose after it announced year-to-date production had averaged 57,100 barrels of oil equivalent per day, ahead of a full-year guidance of 55,000.Petra Diamonds continued to rebound after poor financial results on Friday. The African mining company is up 8.69% after a massive drop on Tuesday, despite Nomura warning on Monday that Petra's 100% tender sales process leaves it more exposed to diamond pricing volatility.Brewer and pub operator Greene King took a hit after HSBC downgraded it to 'reduce' from 'hold' and cut its price target to 780p from 830p. The bank said it was concerned about like-for-like sales growth. FTSE 250 - RisersPremier Oil (PMO) 69.85p +9.83%Petra Diamonds Ltd.(DI) (PDL) 98.85p +8.69%Kaz Minerals (KAZ) 109.90p +5.27%AO World (AO.) 159.10p +4.46%Evraz (EVR) 65.35p +3.73%UBM (UBM) 498.80p +3.68%Vedanta Resources (VED) 480.90p +3.06%Hays (HAS) 154.70p +3.00%AA (AA.) 298.10p +2.94%Investec (INVP) 525.00p +2.94% FTSE 250 - FallersOneSavings Bank (OSB) 389.10p -2.97%Greene King (GNK) 792.00p -1.68%Sophos Group (SOPH) 244.40p -1.45%Daejan Holdings (DJAN) 6,060.00p -1.30%Telecom Plus (TEP) 1,078.00p -1.28%Wetherspoon (J.D.) (JDW) 705.00p -1.26%Shawbrook Group (SHAW) 320.00p -1.08%Fidelity China Special Situations (FCSS) 117.00p -0.93%CLS Holdings (CLI) 1,854.00p -0.86%UDG Healthcare Public Limited Company (UDG) 523.00p -0.85%