The London Stock Exchange Group is among the high risers in the index Monday afternoon after yesterday's bid speculation in the Sunday Times.It was reported Sunday that Abu Dhabi was in talks to acquire a 20% stake in the company from Dubai, as it seeks to take control of the of the financial empire in the Middle East.UK-based housebuilder Taylor Wimpey and retailer JD Sports Fashion are also making gains.Fund manager Gartmore is leading the fallers after speculation saying that rival Henderson could make a takeover bid at 95p per share, a discount to its current share price. Henderson is currently higher on the news.Rumours that Ladbrokes is mulling a bid for internet casino firm 888 have been confirmed by the high street bookmaker, which saw shares fall.It's thought a price of 70p for each 888 share is being discussed, valuing the business at about £240m. FTSE 250 - RisersTaylor Wimpey (TW.) 29.68p +5.10%CPP Group (CPP) 297.60p +4.75%London Stock Exchange Group (LSE) 855.00p +3.89%Drax Group (DRX) 371.90p +3.54%Rank Group (RNK) 138.60p +3.36%JD Sports Fashion (JD.) 885.00p +2.91%Renishaw (RSW) 1,307.00p +2.59%Exillon Energy (EXI) 310.00p +2.48%Charter International (CHTR) 831.50p +2.40%EnQuest (ENQ) 137.60p +2.38%FTSE 250 - FallersGartmore Group Ltd. (GRT) 96.25p -8.16%Dixons Retail (DXNS) 22.90p -5.95%Betfair Group (BET) 983.00p -5.39%St. Modwen Properties (SMP) 160.00p -5.21%Dunelm Group (DNLM) 527.50p -4.09%Avis Europe (AVE) 223.20p -3.67%Lamprell (LAM) 320.60p -2.97%Savills (SVS) 388.30p -2.68%Marston's (MARS) 110.30p -2.39%Home Retail Group (HOME) 192.20p -2.34%