Apple avoided paying taxes on tens of billions of dollars in profits through a complex network of subsidiaries, many with "no declared tax jurisdiction," a US Senate panel has concluded. The Senate investigation, set to be discussed at a hearing Tuesday, stopped short of accusing the US tech giant of anything illegal but two lawmakers on the panel said the tax strategies call for new scrutiny. "Apple wasn't satisfied with shifting its profits to a low-tax offshore tax haven," said Senator Carl Levin, head of the Senate Permanent Subcommittee on Investigations, in a statement Monday. "Apple sought the holy grail of tax avoidance. It has created offshore entities holding tens of billions of dollars, while claiming to be tax resident nowhere." Levin said Tuesday's hearing would "highlight that gimmick and other Apple offshore tax avoidance tactics so that American working families who pay their share of taxes understand how offshore tax loopholes raise their tax burden, add to the federal deficit and ought to be closed." Republican Senator John McCain, another panel member, cited "the highly questionable tax strategies that corporations like Apple use to avoid paying taxes in America." "The proper place for the bulk of Apple's creative energy ought to go into its innovative products and services, not in its tax department," McCain said in a statement. The two senators said they were proposing measures to close these loopholes used by Apple and other multinationals to shield offshore income from US taxes. The Senate report said Apple used a "cost sharing agreement" to transfer intellectual property assets offshore and shift the resulting profits to a tax haven jurisdiction. One subsidiary "reported net income of $30 billion, but declined to declare any tax residence, filed no corporate income tax return, and paid no corporate income taxes to any national government for five years," the report said. The panel said Apple also negotiated a tax rate of less than two percent with the government of Ireland, lower than that the 12 percent statutory rate , to use Ireland as the base for its network of offshore subsidiaries. From 2009 to 2012, the deal allowed Apple to shift $74 billion in worldwide sales income away from the United States to Ireland, the investigators found. The report said Apple has $145 billion in cash and equivalents, of which $102 billion is held offshore to minimize tax liabilities. The panel has called Apple chief executive Tim Cook and others from the California tech giant to testify Tuesday on "methods employed by multinational corporations to shift profits offshore." The hearing comes amid increased scrutiny on offshore holdings of big US corporations, which have hundreds of billions of dollars overseas but are reluctant to bring the funds home because they could be subject to a top tax rate of 35 percent. Cook told The Washington Post he will be making his own proposal to lawmakers, which he argued would make it easier for Apple and other companies to repatriate offshore profits. "If you look at it today, to repatriate cash to the US, you need to pay 35 percent of that cash. And that is a very high number," Cook told the daily. "We are not proposing that it be zero. I know many of our peers believe that. But I don't view that. But I think it has to be reasonable."