Only when instructed, after successful vetting. The sequence is: apply online and pay the processing fee, follow the USCIS instructions for I-140G supporting documents through the official portal, complete vetting, then send the gift on instruction. Money moved earlier is money moved outside the process.
Sequencing the employer's transfer against the official steps
Record the official payment instructions and confirm that the company’s authorization matches the requested transaction. Review the likely EB-1 or EB-2 category and chargeability early, rather than waiting until after the gift. Visa availability, interview and other required steps still govern the outcome.
The published weeks description is not a guaranteed start date. Obtain tax advice on compensation and the worldwide-income rules ordinarily applicable to US permanent residents. Contrast the sequence the process requires with the sequence a corporate finance calendar prefers, because the two rarely coincide.
Funds are sent when instructed and after successful vetting, not when a quarter closes or a budget is about to lapse. A company wanting to transfer early should be told plainly that money moved outside the instructed sequence creates a problem the applicant, not the company, will have to explain. Compare what each party controls as well.
You control document assembly and the accuracy of the record; nobody controls when a visa becomes available or how long review takes, so any commitment about a start date belongs in writing as conditional rather than fixed. Place the resignation decision after the outcome, never before it.