Both Carillion and Balfour Beatty leapt after they confirmed rumours they are in discussions about a possible merger. The preliminary talks are to develop a strategy and outline a business plan for a combined entity, which it said would be "underpinned by the evaluation of achievable synergies, future financing arrangements and a number of other essential supporting workstreams". Lonmin investors were in a cheery mood despite the group slashing its full-year platinum output guidance following the five-month labour strike in South Africa. Bodycote was higher after Berenberg upped its target price from 759p to 776p, upgrading the stock from 'hold' to 'buy'.Meanwhile, shares in Spectris moved sharply lower after the instrumentation and controls company reported lower than expected half-year results. With sales down 5% year-on-year from £566.2m to £539.8m, profits suffered a 10% drop from £75.0m to £67.3m, pushing earnings per share from 48.4p to 43.3p. On a statutory basis profit slumped 62% to £58.6m, while earnings per share declined from 90.9p to 39.4p. Howden Joinery was in the red following strong gains yesterday, which came after it delivered a decent jump in interim profits and reported a strong start to the second half.FTSE 250 - RisersBalfour Beatty (BBY) 252.20p +8.66%Carillion (CLLN) 364.20p +7.59%Countrywide (CWD) 489.30p +5.20%Lonmin (LMI) 240.40p +4.66%Bodycote (BOY) 706.00p +3.14%Essentra (ESNT) 799.00p +2.77%Renishaw (RSW) 1,898.00p +2.71%Regus (RGU) 181.30p +2.66%Interserve (IRV) 645.50p +2.46%Greencore Group (GNC) 281.20p +2.40%FTSE 250 - FallersSpectris (SXS) 1,958.00p -6.54%Howden Joinery Group (HWDN) 352.90p -3.29%Hochschild Mining (HOC) 159.10p -3.22%AO World (AO.) 212.70p -2.97%Cairn Energy (CNE) 179.30p -2.61%BTG (BTG) 606.50p -2.49%Centamin (DI) (CEY) 73.20p -2.40%Derwent London (DLN) 2,725.00p -2.26%Kazakhmys (KAZ) 346.10p -2.23%Vesuvius (VSVS) 461.70p -2.10%NR