Shire, the pharmaceutical group which has agreed to a £32bn takeover by Abbvie, saw its shares decline sharply on Wednesday on concerns that stricter rules on so-called 'tax inversion' in the States could scupper the deal.Sector peer Astrazeneca, which had recently been the target of a failed £69bn bid from Pfizer, also saw its share price droop as hopes faded that the US giant could return later in the future with a higher offer. Pfizer was explicit earlier in the year that it was looking to acquire to Astrazeneca to lower its tax bill.Larger peer GlaxoSmithKline was slightly in the red after going ex-dividend.Precious metals miner Fresnillo was among the best performers after Credit Suisse upgraded the stock from 'underperform' to 'neutral', saying that the business should recover after a "rough patch". The bank hiked its target price for the shares by 39% to 900p.Shares of Fresnillo and sector peer Randgold were also benefiting from the rising prices of gold and silver on Wednesday as precious metals gained on the back of safe-haven demand amid a wider market sell-off.In a similar vein, defensive sectors such as utilities were also performing well, with Centrica, Severn Trent and SSE registering gains.Accounting software group Sage inched higher after appointing former Micro Focus boss Stephen Kelly as successor to longstanding chief executive Guy Berruyer.FTSE 100 - RisersHargreaves Lansdown (HL.) 1,049.00p +4.07%Fresnillo (FRES) 950.50p +2.59%Randgold Resources Ltd. (RRS) 5,110.00p +2.10%Vodafone Group (VOD) 197.55p +0.92%Sage Group (SGE) 370.40p +0.62%Centrica (CNA) 310.10p +0.62%Severn Trent (SVT) 1,885.00p +0.43%SSE (SSE) 1,453.00p +0.41%Carnival (CCL) 2,095.00p +0.24%Coca-Cola HBC AG (CDI) (CCH) 1,377.00p +0.22%FTSE 100 - FallersShire Plc (SHP) 4,571.00p -6.26%AstraZeneca (AZN) 4,152.00p -4.45%Smith & Nephew (SN.) 1,021.00p -4.04%Sports Direct International (SPD) 636.50p -3.56%Ashtead Group (AHT) 864.00p -2.65%ITV (ITV) 201.60p -2.61%Standard Life (SL.) 360.60p -2.54%London Stock Exchange Group (LSE) 1,846.00p -2.48%GKN (GKN) 341.00p -2.46%GlaxoSmithKline (GSK) 1,411.00p -2.39%BC