Investors didn't hang about when Investec warned them to avoid Premier Food's stock, sending it tumbling more than 37%. Following Premier Foods' full-year profit warning on Friday, Investec placed its hold rating and 15p target price under review. In an unscheduled third quarter interim management statement, the food manufacturer revealed that since its third quarter performance has been significantly under expectations, full-year trading profits will be below market forecasts. The story wasn't much different for Talvivaara Mining after Pekka Perä, the firm's chief executive officer, announced he is to hang up his helmet as soon as the company can find a replacement, as the company goes into cash conservation mode. The company said that, in view of the current volatility and uncertainty in the commodity and financial markets, it has developed a revised operating plan and made the strategic decision to focus on maximising profitability of operations rather than the production volume over the remainder of 2011. Dixons was heading north following the joyful news that it had won the Grand Prix at the APG Creative Strategy Awards. The electronics retailer, which shared the prize with the Colombian Ministry of Defence, was comended on acknowledging its particular strengths and weaknesses in the highly competitive category. Morgan Stanley helped boost the share price of Thomas Cook after saying that it believes the troubled travel firm could see its share price double in the coming half year, if it is able to avoid needing to raise equity. FTSE 250 - RisersInternational Personal Finance (IPF) 252.20p +5.79%Dixons Retail (DXNS) 11.71p +5.50%Thomas Cook Group (TCG) 42.74p +5.14%Debenhams (DEB) 61.50p +5.13%Morgan Crucible Co (MGCR) 261.60p +4.43%African Barrick Gold (ABG) 526.50p +3.95%Informa (INF) 337.60p +3.88%Bwin.party Digital Entertainment (BPTY) 117.90p +3.88%Soco International (SIA) 335.00p +3.68%UBM (UBM) 469.30p +3.58%FTSE 250 - FallersPremier Foods (PFD) 6.21p -37.85%Talvivaara Mining Company (TALV) 196.10p -22.67%CSR (CSR) 190.90p -4.07%Grainger (GRI) 86.10p -3.96%Aveva Group (AVV) 1,315.00p -3.73%Renishaw (RSW) 963.00p -3.46%Laird (LRD) 142.50p -3.26%Fidessa Group (FDSA) 1,472.00p -3.22%Ophir Energy (OPHR) 229.40p -3.00%Oxford Instruments (OXIG) 728.50p -2.87%NR