The survey of the 500 most profitable companies this year, by consultancy and market research firm Vietnam Report, said 51.4 percent of businesses considered exchange rate volatility as the biggest challenge this year. For 42.9 percent of respondents the tax burden was the biggest concern. Other factors that affect their profitability are red tape (37.1 percent), global economic instability (31.4 percent) and environmental disasters (25.7 percent). However, 90 percent expected their revenues to rise this year. Eighty percent said their profit had already exceeded last year’s, with another 8.6 percent saying it had drawn level. Almost all (97.1 percent) said the government has stewarded the economy well by curbing inflation and managing the exchange rate adroitly. But they wanted improvements to administrative procedures, infrastructure and access to land. The survey found the telecommunications-information technology sector having the highest return on equity, 30 percent, followed by transportation with 24 percent and pharmaceuticals with 21 percent. The Vietnam Oil and Gas Group or PetroVietnam is the most profitable company this year followed by telecomunications firm Viettel and Samsung Electronics Vietnam Co. Ltd.