After the twelfth month of continuous qualifying employment abroad is complete, and while that year still falls within the three years preceding the petition. Filing early on the strength of earlier contracting is the more expensive mistake.
Waiting a month is cheaper than being denied
The temptation to file at eleven months is understandable when a customer is waiting, and it is a poor trade. A denial costs the fee, the professional time and the schedule, and it puts an adverse decision on the record that has to be explained in any later filing. Waiting completes the qualifying year, produces a clean payroll record and lets the petition state a simple fact rather than argue a contested one. Two related timing points deserve attention. The qualifying year must fall within the three years immediately preceding the petition, so a long gap between the year abroad and the filing can itself become a problem. And time already spent in the United States in L status counts toward the five-year limit, so a specialist who has been shuttling on short assignments should have that history reconstructed before anyone plans a long posting.
Hypothetical example: A Canadian maker of electrical-grid sensors wants to transfer the engineer who created its proprietary commissioning sequence. The project manager should begin by reconstructing the engineer's foreign payroll dates and earlier L admissions, then set the filing timetable around the completion of a qualifying year and the five-year maximum. Technical evidence takes longer than a form: engineering must identify what the individual knows, how it was acquired, and why it is materially different from standard industry knowledge. Filing before the payroll year is complete can turn a straightforward calendar question into a credibility problem. Delaying evidence collection until a customer deadline also invites generic descriptions. A staged plan—employment history first, knowledge proof second, assignment logistics last—allows the company to decide whether a short visit or a later transfer fits the commercial need.