More than one-tenth of the top-share index's constituents are trading in ex-dividend format this morning, which is acting as a millstone around the benchmark's neck.Integrated oil giant BP, which has the fourth highest weighting in the index's constituent list, is adding to the Footsie's woes, as investors react to a report in the Financial Times which suggests that the US Department of Justice (DoJ) is pressing hard for the maximum penalty to be imposed on the British company for its part in the April 2010 Gulf of Mexico oil well disaster.BP and the DoJ are set to square off in a New Orleans court in January next year and the war of words is starting to heat up. Last month, BP asked the court to approve its $7.8bn settlement with fishermen in the Gulf of Mexico and other people in the area who suffered from the oil spill, but judging by a scathing memo filed this week by the DoJ with the New Orleans court, the US authorities are not impressed with BP's settlement, and want to ensure that it does not preclude the court from setting a higher settlement price. "BP's cherry-picked assertions of robust recovery are at best premature judgements on the health of the overall gulf ecosystem," the DoJ claims. The DoJ places more credence in a "multi-year, multi-million dollar natural resource damage assessment" currently being undertaken, which it says is "already showing indication of harm to natural resources".Providing a bit of support for the blue-chip index is insurance colossus Prudential, which is wanted after completing the acquisition of the US unit of reinsurance giant Swiss Re.The acquisition, first announced on May 31st, was made by Pru's indirect wholly-own subsidiary, Jackson National Life Insurance Company, and has now received all necessary regulatory approvals. Jackson has now acquired assets worth around £6.7bn and approximately 1.5m policies, according to a statement earlier this year.FTSE 100 - RisersXstrata (XTA) 938.80p +2.32%Wolseley (WOS) 2,613.00p +1.99%Petrofac Ltd. (PFC) 1,540.00p +1.45%Lloyds Banking Group (LLOY) 33.36p +1.43%Smith & Nephew (SN.) 669.50p +1.29%Burberry Group (BRBY) 1,331.00p +1.22%Randgold Resources Ltd. (RRS) 6,470.00p +1.17%Capita (CPI) 731.00p +1.11%InterContinental Hotels Group (IHG) 1,613.00p +1.07%Prudential (PRU) 778.00p +1.04%FTSE 100 - FallersBP (BP.) 418.65p -4.11%Resolution Ltd. (RSL) 206.80p -3.36%BHP Billiton (BLT) 1,775.00p -2.85%Kazakhmys (KAZ) 585.00p -2.01%Evraz (EVR) 214.70p -1.51%Imperial Tobacco Group (IMT) 2,419.00p -1.23%Weir Group (WEIR) 1,561.00p -1.20%Johnson Matthey (JMAT) 2,338.00p -1.14%Eurasian Natural Resources Corp. (ENRC) 297.40p -1.10%British American Tobacco (BATS) 3,236.50p -1.04%JH