Shares in food and sweeteners manufacturer Tate & Lyle were falling heavily on Friday morning after the stock's rating was cut by Credit Suisse from 'outperform' to 'neutral'. The bank said its greatest concerns is a proposal in Mexico to tax soft drinks which would cut demand the group's high-fructose corn syrup. It has cut its earnings per share estimates for Tate & Lyle by 7-8% and lowered its price target from 930p to 800p.Citigroup has upgraded its rating for supermarket chain Sainsbury from 'sell' to 'neutral', saying it expects a "big improvement" in sales trends in the second quarter."On both sales and earnings we anticipate that Sainsbury's 1H will show substantially more progress than either of its UK rivals. This is not a 'sell' in our opinion," said analysts Alastair Johnston and Pradeep Pratti.Panmure Gordon has maintained its 'hold' rating for catering group Compass ahead of its pre-close trading update next week, but highlighted the company's strong balance sheet and showed optimism about shareholder returns."In our view, Compass remains a high quality, global growth story albeit the valuation in our view is fair and whilst there remains some balance sheet potential, is fairly limited. However further weakness in the share price may provide an opportunity given its defensive and cash generative characteristics."BC