(ShareCast News) - Banks and retailers were among the weakest segments of the market at the start of the week.Share price falls in Italian lenders ahead of the 4 December referendum on constitutional reform appeared to crystallise worries about that country´s banking system and fed negative sentiment towards the wider sector.Acting as a backdrop, some analysts also highlighted to Digital Look the possibility that key regulatory decisions for euro area lenders by the Bank of International Settlements might be postponed until the new US administration was in place.Analysts at UBS echoed that possibility on Monday in a research note sent to clients, alongside the incentives that existed for US and other regulators to push for higher credit risk-weighted assets, which they described as "Europe´s key vulnerability".UBS´s Jason Naper also took note of the European Commission´s proposal for the implementation of holding company requirements, "further reducing the efficiency of bank capital and potentially increasing the impetus to move operations from the UK. Banks are not yet out of the woods."The above weighed on the likes of RBS, Barclays, and Lloyds.Retailers such as Next, Burberry Group, M&S were also weak.In a research note dated 25 November analysts at Goldman Sachs projected a 0.7% drop in UK non-food retail sales in 2017, down from a rise of 1.6% in 2016, due to their forecasts for slower employment growth and rising non-discretionary costs.They estimated that UK disposable personal income would grow by 300 basis points less in 2017.FTSE 100 - RisersRandgold Resources Ltd. (RRS) 5,965.00p 4.28%Fresnillo (FRES) 1,278.00p 3.73%Polymetal International (POLY) 769.50p 3.22%Centrica (CNA) 209.00p 2.40%SSE (SSE) 1,495.00p 2.12%United Utilities Group (UU.) 907.50p 1.45%Bunzl (BNZL) 2,066.00p 1.18%Rolls-Royce Holdings (RR.) 672.50p 0.98%Intertek Group (ITRK) 3,250.00p 0.96%Severn Trent (SVT) 2,231.00p 0.90%FTSE 100 - FallersNext (NXT) 4,820.00p -2.65%Royal Bank of Scotland Group (RBS) 196.20p -2.63%BT Group (BT.A) 350.30p -2.38%Sky (SKY) 769.00p -2.29%CRH (CRH) 2,658.00p -1.96%Burberry Group (BRBY) 1,408.00p -1.95%Paddy Power Betfair (PPB) 8,440.00p -1.92%Schroders (SDR) 2,814.00p -1.92%Vodafone Group (VOD) 195.25p -1.86%Royal Dutch Shell 'B' (RDSB) 2,072.00p -1.85%