The US economy have been relatively strong since the financial crisis in 2008 and financial market and fixed assets return has been high as well. These two factors can cause the US dollar to appreciate against other currencies and lowers the trade deficits. cause the US dollar to depreciate against other currencies and increase trade deficits. cause the US dollar to appreciate against other currencies and increase trade deficits. cause the US dollar to depreciate against other currencies and lowers the the trade deficits