Swiss textile machinery manufacturer Rieter Holding AG today posted a 24 per cent plunge in 2001 net profit to 111.2 million Swiss francs compared to the year-ago period. The company said improved operating profit and sales were offset by a slide in income and tax hikes. Turnover in its textile machinery unit climbed 13.6 per cent, but order inflow slipped 14.3 per cent, while operating profit increased around 10 per cent.