(ShareCast News) - The FTSE 250 is on track to finish the week on a high, with the market up 99.55 points (0.58%) mid-afternoon Friday to 17,216.68 points.Tullett Prebon and ICAP were the biggest risers on the back of confirmation that Tullett Prebon is in discussions regarding the possible acquisition of its rival's global broking business.ICAP confirmed the sale discussions involved the global broking business's associated technology and broking platforms, including iSwap and Fusion, its associated information services businesses and certain of its joint ventures and associates.The announcement followed press reports suggesting the companies were close to announcing some form of deal following months of talks.Thomas Cook Group rebounded after falls on Thursday when the Government announced a halt on all flights between the UK and Sharm al-Sheikh.After the markets closed, Downing Street announced flights from the Egyptian resort to the UK would be permitted to fly to allow UK residents to return home, albeit with more strict security measures.Thomas Cook is one of five airlines that service the city and it is estimated 20,000 British tourists are in the area.However, everything wasn't rosy on the FTSE 250, with the market seeing Synthomer's weakness in its paper business and an uncertain latex outlook.The chemical group issued its third quarter results with strong progress reported across most operations.Management also remained confident in hitting their full-year targets - while volumes in Europe and North America were down on the paper softness, the Construction & Coatings and Functional Polymers segments were seeing further improvement.However, the market was less than impressed, with the company being the market's biggest faller.Amec Foster Wheeler also prevented the market from rising higher, after UBS and Citigroup downgraded the stock from buy to neutral.It came after having suffered heavy losses in the previous session when the oil and gas engineering services company said it was cutting its dividend by half amid tough market conditions.Citigroup said the company's "aggressive change of outlook" and move to protect the balance sheet highlights the fact the depth and length of the downturn continues to be under-appreciated by both oilfield services companies and markets.UBS said one of the key points of its investment case was Amec's above average dividend yield at around 5%, but the decision to halve the dividend in 2016 means the yield is now broadly in line with the European oil services average yield of 3.2% in 2016E and not a reason to be active buyers.FTSE 250 - RisersTullett Prebon (TLPR) 357.20p 8.64%ICAP (IAP) 474.60p 6.99%Aldermore Group (ALD) 267.20p 3.65%Thomas Cook Group (TCG) 116.00p 3.39%Jardine Lloyd Thompson Group (JLT) 876.00p 3.24%esure Group (ESUR) 262.90p 3.14%Virgin Money Holdings (UK) (VM.) 392.30p 2.67%Man Group (EMG) 167.80p 2.63%Jimmy Choo (CHOO) 152.90p 2.62%Centamin (DI) (CEY) 65.50p 2.58%FTSE 250 - FallersSynthomer (SYNT) 318.50p -5.49%Morgan Advanced Materials (MGAM) 267.30p -4.50%Amec Foster Wheeler (AMFW) 550.50p -4.09%Premier Oil (PMO) 77.00p -3.75%Petrofac Ltd. (PFC) 773.00p -3.31%Petra Diamonds Ltd.(DI) (PDL) 73.35p -3.10%Aggreko (AGK) 928.50p -2.57%Cobham (COB) 275.00p -2.14%Evraz (EVR) 80.80p -2.12%Kaz Minerals (KAZ) 112.00p -2.10%