Rio Tinto may have swung to its first-ever annual loss in 2012, but Nomura has kept its 'buy' rating and 3,700p target price for the stock, calling its full-year results 'solid' with adjusted profits coming in ahead of forecasts.The broker labelled Rio as an attractive and relatively low-risk exposure to the mining sector in a "volatile and unpredictable" macroeconomic environment.Following a tough year for security solutions group G4S, Investec has raised its rating for the stock from 'hold' to 'buy', saying that the company is well-placed to recover in 2013."G4S has faced a series of setbacks in the UK, with the mishandled Olympics contract followed by a failure to secure recent high-profile prisons and police opportunities. However, we believe concerns over exclusion from government outsourcing are overdone, and that the group is poised to benefit from a greater flow of programmes into 2013."Panmure Gordon has retained its 'hold' rating and 380p target price for soft drinks group Britvic after Wednesday's announcement that the Office for Fair Trading (OFT) has referred the firm's proposed merger with AG Barr to the Competition Commission.Panmure said: "This decision seems bewildering given the relatively small share each of these brands has of the £9bn GB soft drinks market and the fact that Coca Cola and Private label combined account for c.50% of the GB Take Home market."BC