Investors should switch their preference from housebuilders to contractors, according to Westhouse Securities, which said it sees downside risks in the housing sector.The broker recommended using a recent rally as a "selling opportunity for housing-related stocks", including merchants, distributors and estate agents. It said that the contracting sector is more favourable with the "political imperative [...] shifting back to infrastructure".Oriel Securities has raised its rating for Vodafone but said it is "cautiously upgrading to a 'hold' from 'reduce' with a number of uncertainties still ahead."Until the group starts to regain share in Europe, without yet more extra spend, investors are more likely to doubt the dividend is safe than be reassured by it. We have at least two more tough quarters ahead, according to Vodafone. So 'hold', but also be very vigilant."Credit Suisse sees "great momentum" at Next and has raised its profit forecasts for the high street retailer, lifting its target price from 6,500p to 6,800p.Despite the upgrades, Credit Suisse said: "However given the demanding long-term assumptions, the likelihood that Next's core customer is relatively sensitive to higher interest rates, and with the shares having notably outperformed during the recent sell-off, we maintain our 'neutral' rating."Numis Securities has upgraded support services and construction group Interserve from 'add' to 'buy', saying that the market is not appreciating its organic and acquisitive growth potential.The broker highlighted that the stock initially performed well in response to the £250m purchase of Initial Facilities (IF) from Rentokil Initial in late February. "But subsequent weakness means the shares are now back to when the deal was announced. We believe this is not justified," Numis said.BC