Bid talk pushed Invensys higher. The engineering firm denies press reports that it has received an approach. Chief executive Ulf Henriksson told the Telegraph that China Southern Rail has agreed in principle the possibility of acquiring Invensys, but no "discussions regarding a possible offer for the company or about a strategic partner taking a minority stake" have taken place.Platinum miner Lonmin has returned to profit and recommenced dividend payments, as higher metals prices offset the ongoing technical problems at its main furnace. Profits in the year to September 2010 came in at $240m, compared to a loss of $272m last time. Revenues rose from $1.06bn to $1.59bn. A final dividend of 15 cents a share is proposed. The market was pleased that BHP Billiton has ended its battle to buy Canada's Potash Corp for around $40bn and decided to undertake a $4.2bn share buyback instead.Serco, the outsourcing company, is having a rare positive day after it said that it is on track to deliver on its financial guidance for 2010.Rolls-Royce has fallen back on further consideration of the costs of rectifying its engine fault. FTSE 100 - RisersInvensys (ISYS) 343.00p +7.59%Lonmin (LMI) 1,839.00p +4.07%Weir Group (WEIR) 1,695.00p +3.04%Petrofac Ltd. (PFC) 1,531.00p +2.55%Marks & Spencer Group (MKS) 403.10p +2.52%ICAP (IAP) 480.60p +2.34%Autonomy Corporation (AU.) 1,419.00p +2.16%British Airways (BAY) 270.20p +1.81%Serco Group (SRP) 572.50p +1.69%BHP Billiton (BLT) 2,402.50p +1.69%FTSE 100 - FallersRolls-Royce Group (RR.) 598.50p -2.05%International Power (IPR) 420.50p -0.94%Inmarsat (ISAT) 670.00p -0.89%Legal & General Group (LGEN) 99.50p -0.60%Whitbread (WTB) 1,735.00p -0.57%TUI Travel (TT.) 202.60p -0.54%AstraZeneca (AZN) 3,022.00p -0.48%Smith & Nephew (SN.) 591.50p -0.42%Centrica (CNA) 339.00p -0.35%Compass Group (CPG) 540.50p -0.28%