The IRS requires a flat 30% withholding on ALL types of payments to foreign national individuals UNLESS: The individual has a U.S. tax identification number (SSN or ITIN) and qualifies for a tax reduction under the tax treaty between the U.S. and their country of tax residency.
Self-employment Tax: Even though the Canadian company doesn't issue a 1099,you are still responsible for reporting all your income, including this, on your US tax return.
Payments to a foreign corporation in exchange for personal services performed in the US by either a US citizen or alien is considered to be US-sourced income and is usually subject to withholding. (Can be wages or self-employment income.)
Today, it's possible to hire independent contractors from any part of the world, thanks to improvements in technology and communications. It's a great idea to consider Mexico if you're looking to expand your team. Its proximity and strong economic ties to the US are definite advantages.
If you're a sole-proprietor, self-employed or a certain type of partnership, you must fill out your T1 General, that's your standard personal income tax return. You must also complete a separate T2125 “Statement of Business or Professional Activities”. This is where you specify: Business and professional income earned.