Hello :) I reside in Canada, work for a US company, but am paid through a Canadian 'numbered company' in canadian dollars. I travel into the US roughly 40 days a year for meetings with my boss, trade shows, etc. I started to have issues crossing the border, so my employer attained an L1 visa for me. Do I need to submit a US tax return?

Many thanks!

This is from IRS pub 901.
Income that residents of Canada receive for personal services performed as employees (dependent personal services) in the United States is exempt from U.S. tax if it is not more than $10,000 for the year. If the income is more than $10,000 for the year, it is exempt only if:
•The residents are present in the United States for no more than 183 days in any 12-month period beginning or ending in the tax year, and
•The income is not paid by, or on behalf of, a U.S. resident, and is not borne by a permanent establishment in the United States.