Note "For U.S. stocks, while, there is an exemption from withholding tax under the Canada-U.S. tax treaty for U.S. dividends paid to an RRSP or RRIF, this exemption does not apply to U.S. dividends paid to a TFSA." So until POET starts paying dividends ok to trade in TFSA. Nevertheless POET shareholders should be given the option to choose whether they own TSX or NASDAQ or both. Each persons situation may be different and they may want one or the other or both (given my circumstances I would probably choose both (I like a balance of currency risk in my portfolio). Hopefully POET will hear it's Canadian shareholders and offer both. Here is link to CRA TFSA and National Post article http://www.cra-arc.gc.ca/tfsa/ http://www.financialpost.com/m/wp/blog.html?b=business.financialpost.com//personal-finance/taxes/when-a-tax-free-savings-account-isnt-tax-free