There were reports in this morning's papers that RSA, Resolution, Switzerland's Zurich Financial Services and Germany's Allianz considered a multibillion-pound break-up bid for insurer Aviva. Credit Suisse has commenced coverage of building supplies group Wolseley with an outperform recommendation. National Grid has appointed former Cadbury finance director Andrew Bonfield as its new finance director. Satellite operator Inmarsat has been hit by rumours that US hedge fund Harbinger, which holds a 28% stake in the company, may sell some shares.Elsewhere, oil and mining companies dominate the fallers. BP and Cairn Energy are falling due to the lower crude oil price. Anglo-Swiss miner Xstrata's weakness is thought to be due to rumours that Singapore-based Sin-Tang Developments is mulling a rival bid to Xstrata's $416m offer for Australia's Sphere Minerals.FTSE 100 - RisersWolseley (WOS) 1,628.00p +2.91%National Grid (NG.) 551.50p +1.94%Aviva (AV.) 401.10p +1.67%Standard Chartered (STAN) 1,863.50p +1.55%British Land Co (BLND) 479.70p +1.27%Man Group (EMG) 218.90p +1.25%BAE Systems (BA.) 347.30p +1.22%BT Group (BT.A) 144.40p +1.12%Royal Bank of Scotland Group (RBS) 48.17p +1.05%Barclays (BARC) 302.65p +0.97%FTSE 100 - FallersInmarsat (ISAT) 651.00p -2.62%Cairn Energy (CNE) 449.10p -1.75%Shire Plc (SHP) 1,398.00p -1.55%Johnson Matthey (JMAT) 1,740.00p -1.47%BP (BP.) 434.45p -1.37%Xstrata (XTA) 1,226.00p -1.25%Invensys (ISYS) 300.50p -1.22%Antofagasta (ANTO) 1,233.00p -1.20%Kazakhmys (KAZ) 1,446.00p -1.03%WPP Group (WPP) 699.50p -0.99%