TUI Travel shares jumped after it announced that it had agreed the terms of a merger between itself and parent company TUI AG, a move that will create the world's "number one integrated leisure tourism business". Under the terms of the agreement, TUI Travel investors would receive 0.399 new TUI AG shares for every TUI Travel share.UBS helped housebuilders higher after it said that the positive fundamentals of the sector remain unchanged despite measures by the Bank of England announced yesterday to cool the housing market. It said that while a "policy over-reaction" is undoubtedly the biggest risk to the sector, this risk has already been largely priced into the market and that future intervention will be "gradual and measured". Barratt Developments, Persimmon and Travis Perkins were all firmly higher. Engine maker Rolls-Royce was rising on rumours that Airbus it close to upgrading its A330 fleet with the Rolls as its sole engine supplier.Meanwhile, target price cuts from Societe Generale helped to push both Petrofac (1,600p to 1,480p) and Standard Chartered (1,550p to 1,450p) into the red.The latter was also hit by a 'sell' reiteration from Canaccord Genuity, which cut its own target price from 1,200p to 1,000p.Publishing peer Reed Elsevier fell after Barclays Capital lowered its recommendation on the stock to 'equal weight' and trimmed its target price from 1,020p to 1,005p.FTSE 100 - RisersTUI Travel (TT.) 406.60p +4.26%Barratt Developments (BDEV) 375.50p +3.47%Rolls-Royce Holdings (RR.) 1,065.00p +1.82%Aviva (AV.) 508.50p +1.74%Shire Plc (SHP) 4,609.00p +1.59%Randgold Resources Ltd. (RRS) 4,903.00p +1.55%Persimmon (PSN) 1,277.00p +1.43%Travis Perkins (TPK) 1,647.00p +1.42%Admiral Group (ADM) 1,536.00p +1.39%BAE Systems (BA.) 430.50p +1.29%FTSE 100 - FallerseasyJet (EZJ) 1,451.00p -1.56%BG Group (BG.) 1,256.00p -1.45%Petrofac Ltd. (PFC) 1,207.00p -1.31%Standard Chartered (STAN) 1,190.00p -1.08%Meggitt (MGGT) 505.00p -0.98%Reed Elsevier (REL) 933.50p -0.95%Hargreaves Lansdown (HL.) 1,255.00p -0.87%Mondi (MNDI) 1,073.00p -0.83%GKN (GKN) 366.50p -0.79%CRH (CRH) 1,521.00p -0.65%NR