Shire's shares have spiked higher on rumours that Allergan could bid for the company in an effort to fend off a hostile takeover attempt by Valeant Pharmaceuticals. Bloomberg cited an analyst at SunTrust Robinson Humphrey who said that a bid is "imminent" and "makes strategic sense" for the US company.Royal Dutch Shell has announced plans for the initial public offering (IPO) of Shell Midstream Partners, one of its wholly-owned subsidiaries. The business, which will be listed on the New York Stock Exchange under the ticker symbol SHLX, was initially formed as a vehicle to own, operate, develop and acquire pipelines and other midstream assets.BP and BG Group were both making gains as crude prices continued to climb.Miners were broadly higher, having taken quite a hit in yesterday's session. Rio Tinto and BHP Billiton were both strong risers this afternoon. Meanwhile, heavyweight utilities groups Severn Trent and United Utilities were both trading lower this morning after going ex-dividend. WPP was also in the red after Chief Executive Martin Sorrell reported that trading in May was not as strong as April, although it was satisfactory, and he said second quarter trading could surpass its robust set of results in the previous three months.FTSE 100 - RisersShire Plc (SHP) 3,829.00p +4.62%Associated British Foods (ABF) 3,053.00p +2.11%Royal Dutch Shell 'B' (RDSB) 2,539.50p +2.03%Royal Dutch Shell 'A' (RDSA) 2,412.00p +1.71%BP (BP.) 512.90p +1.34%Vodafone Group (VOD) 197.80p +1.31%Mondi (MNDI) 1,070.00p +1.23%Rio Tinto (RIO) 3,083.00p +1.12%BHP Billiton (BLT) 1,873.00p +1.11%AstraZeneca (AZN) 4,412.00p +1.05%FTSE 100 - FallersUnited Utilities Group (UU.) 861.50p -2.77%Severn Trent (SVT) 1,922.00p -2.39%WPP (WPP) 1,259.00p -2.25%IMI (IMI) 1,532.00p -2.05%Aberdeen Asset Management (ADN) 434.60p -1.70%Diageo (DGE) 1,863.00p -1.35%William Hill (WMH) 336.60p -1.29%Sports Direct International (SPD) 756.00p -1.24%Standard Chartered (STAN) 1,285.50p -1.23%Travis Perkins (TPK) 1,576.00p -1.19%NR