Merchant Securities has upgraded its rating on PV Crystalox Solar, the solar power wafers manufacturer, from sell to hold after the stock's recent underperformance.Revenue was up from $59.6m to $78.7m in the six months to 30 June, while adjusted pre-tax profit (excluding a currency impact) rose from €12.4m to €20.6m.However, wafer shipment volume was 204MW, below the 210-225MW guidance earlier in the year but in line with a later update."Average selling prices of wafers had been maintained but pricing remains under pressure. Despite expecting to ship between 400MW and 450MW of cells for the year, the impact on pricing will ensure the group reports a loss in H2 as well," said analyst Julian Tolley."Having gone to a sell at 44p at the end of June, the price has fallen far enough and [we] rate the group a hold," with a target price of 20p.However, the broker suggests that if the price falls below 16p, "buy on weakness".Shares rose 1.27% to 20p at 12.09pm.BC