Decide it before filing if exercise is likely soon or if the diluted numbers already sit near half. If exercise is remote and conditional, the file can proceed on the present ownership while the risk is documented. Either way, treat the answer as a fact-specific legal decision, not a scheduling preference.
Watch ownership after the visa is issued
Set milestones instead of a promised finish date: cap table confirmed, option reviewed, funding trail assembled, packet checked. After that, remember that a visa's expiry date and the period of stay recorded on an I-94 are different things, and that E-2 is a nonimmigrant status resting on an intention to depart when it ends. Review a planned exercise before it occurs when possible, and assess any actual ownership change promptly rather than waiting for the next extension or entry.
The usual structure is an escrow arrangement whose release is conditional only on issuance of the visa, together with spending that has already happened and could not be recovered if the business failed: a signed lease, deposits on machinery, fit-out work, inventory. The common answer is a signed agreement with funds held in escrow and released on approval, prepared with counsel before signature rather than after.