In reaction to fourth quarter results from Marks and Spencer, broker N+1 Singer said the lack of visible revenue improvements was continuing to test investor resolve, but that these numbers provided some small encouragement, enough to maintain a 'buy' recommendation. Singer analysts Matthew McEachran and Mark Photiades said there was "no doubting the massive amount of change being implemented across the group", both in terms of customer-facing and back-of-house projects, and should these changes gain traction the potential is "significant", especially for cutting costs. UBS has upgraded its rating for telecoms giant BT from 'sell' to 'neutral', saying that the stock's current valuation is no longer expensive.However, while the shares are down from their record highs reached in February, the bank said it remains "relatively pessimistic" on the investment case. "BT avoids many of the sector's risks but has its own. In our view consensus remains too optimistic over the ease of a wholesale deal on sports with Sky, the ability of BT to recoup Sports and the impact of mobile spending on cash flow," said UBS analysts Nick Lyall and Michael Hill.Numis Securities has kept its 'hold' recommendation on Mothercare but highlighted an "encouraging underlying improvement" at the baby products, clothing and toys retailer."The recent sharp fall in the share price leaves the valuation looking attractive on a sum-of-the-parts basis, but with earnings risk unlikely to have entirely passed and the senior management/recovery strategy yet to be clarified, we maintain a 'hold' recommendation."Investec has lifted its target price for manufacturing and research group Oxford Instruments from 1,400p to 1,500p after a pick-up in trading in its fourth quarter."In [financial year ending] 2015, however, the benefits will be offset by the impact of non-repeating projects, operational problems at Omicron, a rising tax rate and currency headwinds," Blogg and Dyett said. While the company is said to have "the potential for significant growth", Investec has kept a 'hold' rating, "pending clearer evidence of a sustained recovery in Oxford Instruments' markets".BC