Big Yellow Group, the FTSE 250 self-storage firm, saw its shares dive after it warned that, due to proposals in yesterday's governmental Budget, it may need to charge value-added tax (VAT) to its customers from October 1st 2012.Essar Energy also fell, despite news it has commissioned a further two units at its Vadinar refinery in India, leaving just one additional unit remaining to be commissioned as part of the 1.81bn-dollar phase one expansion project. Regus was rising following the launch of an online trading portal after it conducted research which revealed that 50% of UK respondents see online advertising as one of the top channels to find new customers in the next three years, as reported by incentivetravel.co.uk. Celia Donne, Regional Director at Regus said: "The rise and rise of business social media networks mean that today they are as essential a tool to finding new customers as face-to-face interaction."FTSE 250 - RisersRegus (RGU) 115.00p +7.38%easyJet (EZJ) 456.50p +2.86%Telecity Group (TCY) 727.00p +2.32%William Hill (WMH) 247.90p +1.97%Dixons Retail (DXNS) 19.15p +1.86%Debenhams (DEB) 79.70p +1.79%Talvivaara Mining Company (TALV) 249.80p +1.59%Ladbrokes (LAD) 154.90p +1.57%Spectris (SXS) 1,782.00p +1.48%Micro Focus International (MCRO) 460.50p +1.21%FTSE 250 - FallersInternational Personal Finance (IPF) 249.00p -7.54%Aquarius Platinum Ltd. (AQP) 148.90p -6.76%Essar Energy (ESSR) 141.10p -5.49%Greggs (GRG) 520.50p -5.28%Ferrexpo (FXPO) 305.60p -4.92%Centamin (DI) (CEY) 74.95p -4.40%Gem Diamonds Ltd. (DI) (GEMD) 298.40p -3.93%Big Yellow Group (BYG) 298.60p -3.68%Exillon Energy (EXI) 186.60p -3.67%Cookson Group (CKSN) 690.50p -3.56%NR