Associated British Foods was in the top spot on the FTSE 100 after the company announced its intention to expand its fast-growing Primark brand into the US towards the end of next year.Panmure Gordon upgraded its rating for the stock from 'hold' to 'buy'. saying: "This is sooner than we had anticipated, and whilst Primark will continue its measured approach to expansion, in our view this significantly increases the growth potential of Primark." Interim results from the company also came in ahead of forecasts.The potential value of AstraZeneca's (AZN) drug pipeline is still under-appreciated by the market, with or without a bid from US pharmaceutical peer Pfizer, according to Citigroup, comments which helped push the stock firmly into positive territory. The bank upgraded its rating for the stock from 'neutral' to 'buy' and hiked its target price for the shares from 3,500p to 4,900p. Citi sees an "extreme undervaluation" of AZN's early- to mid-stage oncology pipeline and estimates at least 26% upside to consensus earnings per share after 2017. Wolseley's share price was also making gains after Credit Suisse upgraded the stock from 'neutral' to 'outperform', saying that it foresees substantial capital returns at the plumbing and building materials group. "Our upgrade to WOS is primarily focused on the potential for capital return - we see potential for 1,400p/share over next five years, equal to circa 40% of market cap - but this must be considered alongside a robust trading outlook, a quality management team, a stock that has underperformed its peer group in the past year and a compelling valuation," Credit Suisse said. Meanwhile, Antofagasta was trading firmly in the red after going ex-dividend, meaning that from today new investors won't be able to obtain the company's latest payout. High street sporting goods retailer Sports Direct was also lower after seeing a slight slowdown in growth in the fourth quarter. The company also warned of "further uncertainty" arising from its decision to cancel a controversial bonus payout to founder Mike Ashley earlier this month.Morrison was also in the red after JP Morgan cut its target price from 175p to 150p and stayed with its 'underweight' rating.finnCap has reiterated its 'hold' rating and 1,000p target price for chip designer ARM Holdings after the company's first-quarter results showed strong licensing revenues and weak royalties. "Overall, the company remains on track for market expectations but is just not showing the growth rates to see the shares push beyond the current price-to-earnings ratio of 40."FTSE 100 - RisersAssociated British Foods (ABF) 2,961.00p +8.78%Admiral Group (ADM) 1,397.00p +2.49%AstraZeneca (AZN) 4,045.50p +2.16%Royal Mail (RMG) 531.50p +1.82%Resolution Ltd. (RSL) 294.70p +1.52%Tesco (TSCO) 296.85p +1.52%Wolseley (WOS) 3,411.00p +1.49%Experian (EXPN) 1,122.00p +1.35%William Hill (WMH) 336.40p +1.20%Land Securities Group (LAND) 1,070.00p +1.13%FTSE 100 - FallersAntofagasta (ANTO) 795.50p -5.80%Centrica (CNA) 329.40p -4.49%Hargreaves Lansdown (HL.) 1,199.00p -3.85%Old Mutual (OML) 196.40p -3.73%Sports Direct International (SPD) 799.00p -3.73%Morrison (Wm) Supermarkets (MRW) 196.90p -3.53%ARM Holdings (ARM) 950.00p -3.36%Ashtead Group (AHT) 875.00p -2.83%Standard Chartered (STAN) 1,281.50p -2.29%Coca-Cola HBC AG (CDI) (CCH) 1,484.00p -2.24%NR