(ShareCast News) - An upbeat outlook for margins from Tesco boosted the wider sector gauge.The company's shares rocketed to their best levels since late-summer 2015 - setting a fresh 52-week in one fell swoop - after management reported that UK like-for-like (LFL) sales doubled to 0.6% and operating profits grew 38.4% to £515m as chief executive Dave Lewis continued to turn around the supermarket colossus, which he plans accelerate with a new set of growth "ambitions".While also aiming to strengthen the customer offer, Lewis's ambition is to lift group operating margin from its current 2.2% to 3.5-4.0% by the 2019/20 financial year, helped by cost cutting and a solid level of capital expenditure.Life insurers were also higher after NN Group announced an all-cash €5.30 per share buy-out offer for its Dutch rival Delta Lloyd for a 29% premium on its closing price in the previous session.Oil&Gas producers were also higher after the Energy Information Administration, the US Department of Energy's statistical arm, reported a surprise 3.0m barrel drop in US crude oil stockpiles.As 1546 BST front month Brent crude oil futures were up by 1.68% to $51.74 a barrel on the ICE.Defensive issues such as tobacco and utilities were on the backf-oot, with shares in the latter pressured by downbeat comments out of analysts at RBC.The broker's analysts upped their target price on Pennon from 925p to 950p while reiterating their 'underperform' on shares of both."We believe M&A potential is the only true relative attraction for investors buying (or holding onto) SVT and UU at current trading levels. Both also offer safety and inflation protection amidst Brexit, but so does Pennon, plus more. We think both SVT and UU have healthy financials and are led by respectable management, but with implied total returns of -5% (SVT) and +4% (UU), versus PNN's +10% and SX6P's +18%, we see Underperform as appropriate," RBC said in a research report sent to clients.Top performing sectors so far todayFood & Drug Retailers 3,131.28 +6.50%Life Insurance 7,240.21 +0.65%Industrial Metals & Mining 1,829.89 +0.43%Oil & Gas Producers 7,672.00 +0.31%Technology Hardware & Equipment 2,178.38 +0.27%Bottom performing sectors so far todayTobacco 57,297.05 -2.18%Gas, Water & Multiutilities 6,578.35 -2.11%Real Estate Investment Trusts 2,887.54 -1.89%Fixed Line Telecommunications 4,379.97 -1.41%Software & Computer Services 2,095.08 -1.39%