WASHINGTON (Bloomberg) US companies face the sixth-highest effective tax rate in the world, according to a study by PricewaterhouseCoopers LLP.The tax rate for the largest US companies between 2006 and 2009 was 27.7 percent, compared with a non-US average of 19.5 percent, according to the study released yesterday. Companies based in Japan, Morocco, Italy, Indonesia and Germany faced higher tax rates. Excluding the US, companies based in industrialised countries had an average rate of 22.6 percent.“Without effective business tax reform, we’re going to continue to slip behind competitors,” said John Engler, president of the Business Roundtable, an association of chief executives based in Washington that commissioned the study.The report may help shape the debate over rewriting the US tax code. President Barack Obama has asked Congress to lower the 35 percent corporate tax rate and remove tax credits and deductions to make up for the forgone revenue.Business groups also want the US to switch to a territorial tax system, which wouldn’t tax US companies on profits they earn in other countries. The US requires companies to pay the top corporate rate of 35 percent on profits earned outside the country, though it allows companies to defer taxation until they bring the profits home. Other countries, including Japan and the UK, have recently switched to a territorial system.Except for the US, all other major industrialised countries levy value-added taxes that help cover the cost of government and are used to hold down corporate tax rates.The report doesn’t take into account accelerated depreciation and other timing incentives built into the US tax system, and that makes the difference between the US and other countries look bigger than it is, said Martin Sullivan, a contributing editor at Tax Analysts, a non-profit organization in Falls Church, Virginia.“Although it is contrary to the authors’ purpose, the study overall shows US multinational tax burdens are not much different than tax burdens of multinationals in other major economies,” he said in an e-mail.