News of challenging market conditions from pub owner Punch Taverns weighed on rivals. It also plans to raise about £350m through a placing and open offer and buy outstanding convertible bonds via a tender offer.Enterprise Inns and Marston's are among the casualties.Heritage Oil leads the mid-caps Monday. Last week, it announced plans to merge with Turkish exploration and production group Genel.If the deal goes ahead the company should be big enough to join London's FTSE 100 index. FTSE 250 - RisersHeritage Oil (HOIL) 532.00p +5.24%PayPoint (PAY) 515.00p +3.78%Cranswick (CWK) 617.50p +2.40%Hansard Global (HSD) 134.75p +2.08%Telecom Plus (TEP) 275.00p +1.85%BSS Group (BTSM) 286.00p +1.78%Fisher (James) & Sons (FSJ) 433.00p +1.64%Robert Wiseman (RWD) 362.75p +1.61%Close Brothers Group (CBG) 678.00p +1.42%Hikma Pharmaceuticals (HIK) 425.00p +1.19%FTSE 250 - FallersAshtead Group (AHT) 56.75p -6.58%SVG Capital (SVI) 103.50p -6.33%Enterprise Inns (ETI) 141.00p -6.00%Barratt Developments (BDEV) 168.25p -5.21%Helical Bar (HLCL) 319.25p -5.13%Wellstream Holdings (WSM) 542.50p -4.82%Hays (HAS) 90.50p -4.23%DS Smith (SMDS) 68.75p -4.18%Brit Insurance Holding (BRE) 185.75p -4.13%Marston's (MARS) 154.00p -4.05%