"Therefore, we recently imposed tariffs on $250 billion of Chinese goods - and now our treasury is receiving billions of dollars a month from a country that never gave us a dime".
New tariffs could kick in on 1 March when a 90-day trade war truce ends.
The study also underlines that while some countries will see a surge in their exports, negative global effects are likely to dominate. But the Obama administration and others before it, Sheets said, declined the offers of state-directed purchases in favor of urging China needed to move "away from central planning".
He is due to travel to Beijing next week for the third round of talks aimed at resolving the dispute, which has imposed steep punitive tariffs on $360 billion in two-way trade, weighing on the manufacturing sectors in both countries.
The US and China have a deadline of 1 March to strike a deal, or the US has said it will increase tariff rates on $200bn (£152bn) worth of Chinese goods from 10% to 25%.
"The implications are going to be massive", Pamela Coke-Hamilton, UNCTAD's head of worldwide trade, said at a news conference in Geneva on Monday.
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Smaller and poorer countries will struggle to cope with such external shocks, said Coke-Hamilton. It also warned that the effects could be felt everywhere.
"There'll be currency wars and devaluation, stagflation leading to job losses and higher unemployment and more importantly, the possibility of a contagion effect, or what we call a reactionary effect, leading to a cascade of other trade distortionary measures", Ms Coke-Hamilton said.
The study indicates that European Union would be the victor, capturing around $70bn of new exports.
Unless the USA and Chinese agree to drop their tariff dispute by 1 March, duty on each country's products will rise to 25 per cent, up from the current 10 per cent level. It also did nothing to remove the underlying cause - Chinese retaliatory tariffs - of last year's collapse in USA soy exports to China.
The report indicated that the European Union stood to benefit the most, with companies in the bloc likely to capture around $50 billion of Chinese exports to the US and about $20 billion of USA exports to China.
Australia, Brazil, India, Philippines, Pakistan and would also notice "substantial effects relative to the size of their exports", it said.
Although these figures don't represent a large slice of global trade - which was worth about $17 trillion in 2017 - for many countries they make up a substantial share of exports. One major concern is the risk that trade tensions could spiral into currency wars, making dollar-denominated debt more hard to service.