(ShareCast News) - The FTSE 250 has rebounded after a poor start to the week, with the market in the black by mid-afternon Wednesday at 17,097.44, up 57.62 points (0.34%). TalkTalk led the market after it surprised all by lifting its interim dividend, as it estimated the one-off financial impact of the October cyber attack between £30m and £35m. It said EBITDA fell to £90m in the first half of the year from £110m in the same period last year, missing expectations of around £98m. However, it raised its interim dividend 15% from last year to 5.29p - a move that is likely to surprise analysts and investors who had been expecting a cut. Revenue rose 4.7% to £912m, beating expectations.Ophir Energy also had a good day after it finalised commercial terms for LNG offtake from the Fortuna FLNG Project. It said it is now in the process of signing heads of agreement with a shortlisted group of counterparties, all of which are globally established LNG Buyers. The contracts have been met with strong interest from buyers with the total requested demand exceeding the available off-take from the project. The company also provided a trading update and highlighted that its production for the year to 9 November averaged 13,400 barrels of oil equivalent per day (boepd), with full year production expected to be above previous guidance at approximately 12,700 boepd.Icap also saw big gains after it posted half-year results that showed group revenues declined 4%, but that the businesses it has retained both enjoyed positive sales growth. The company also confirmed the sale of its voice broking unit to Tullett Prebon. It said its post trade risk and information division increased revenues by 8% on a constant currency basis and electronic markets saw a rise of 1%, which was offset by a decrease of 14% in the outgoing global broking arm.However Tullett Prebon didn't come of well out of the deal with Icap, with the company leading the market's fallers. Tullett will issue a parcel of new shares greater than its current share capital such that once the deal is completed, Icap will own 56% of the merged entity before distributing 36.1% of Tullet to its own shareholders. Once the deal is concluded, current Tullett shareholders will own 44% of the enlarged company, 36.1% by Icap shareholders and the remainder by a NewCo holding company of the Icap business. Tullett will also take on gross debt of £330m with the acquisition and the share issue means the deal is expected to be dilutive in first year.Tullow Oil also had a poor showing on the market, after it adjusted the full year production guidance from its West Africa operations and confirmed revenue and costs are in line with annual expectations. It lowered oil production guidance from between 66,000 to 70,000 barrels per day (bpd) to 66,000 to 67,000 bpd, adding full year production from the Jubilee field in Ghana is expected to be approximately100,000 bpd. However it said trading has remained in line with expectations since the start of the year, with revenue and costs largely in line with annual forecast. Tullow expects full year operating cashflow before working capital and tax to be around $1bn.FTSE 250 - RisersTalkTalk Telecom Group (TALK) 242.50p 11.60%Ophir Energy (OPHR) 102.00p 8.11%Sophos Group (SOPH) 270.50p 7.43%ICAP (IAP) 497.60p 5.49%Just Eat (JE.) 461.60p 4.89%Ultra Electronics Holdings (ULE) 1,820.00p 4.30%Kaz Minerals (KAZ) 88.00p 3.71%Indivior (INDV) 201.00p 2.76%OneSavings Bank (OSB) 399.00p 2.65%BTG (BTG) 534.00p 2.59%FTSE 250 - FallersTullett Prebon (TLPR) 318.50p -11.28%Tullow Oil (TLW) 199.20p -6.74%Petra Diamonds Ltd.(DI) (PDL) 62.10p -4.31%Centamin (DI) (CEY) 60.60p -3.19%esure Group (ESUR) 247.60p -2.94%Jimmy Choo (CHOO) 151.00p -2.58%Grafton Group Units (GFTU) 671.00p -2.33%SIG (SHI) 123.60p -2.29%P2P Global Investments C (P2P2) 958.00p -2.24%Hunting (HTG) 337.70p -2.09%