Trade Trends and Economic Effects (3) U.S. and Canadian Foreign Direct Investment Both stock and flow of investment increased markedly during the free trade era. While Canada is not the largest investor in the United States, the United States was the largest destination for Canadian FDI in 2011, with a stock of $211 billion, an increase from $26.6 billion in 1988. Approximately 40.3% of Canadian FDI is invested in the United States