Before the source-of-funds work is finalized, because the documentation follows the structure and the destination of the funds. It also affects how quickly a filing can be made, which matters when a family member is close to an age limit.
Decide the structure, then build the money file around it
Investors sometimes assemble a general funds file and then choose a structure, which produces rework. The tracing has to show the path of the money to its destination, so knowing the destination first makes the file coherent. Where a family is watching a child's age, the sequencing question becomes sharper still, and it is worth asking counsel directly what each option would mean for the likely filing date. Do not let a project's own deadline drive the decision on its own; a project that requires a commitment before diligence is complete is asking the investor to take a risk that has nothing to do with immigration. A short delay to complete diligence is almost always cheaper than a commitment made without it.
Hypothetical example: Tomas owns a small self-storage portfolio and wants to sell one property to fund an EB-5 investment. An opening assessment aligns the sale closing, tax records, funds transfer, project documents, petition preparation, and later conditional-residence recordkeeping. Closing statements and bank trails settle when capital became available and how it moved. Do not assume petition approval itself provides residence; the subsequent immigrant-visa or adjustment process has its own sequence. Timing also continues after admission because removal of conditions depends on preserving investment and job evidence. A late sale or incomplete transfer trail may be more damaging than a later filing date.