Filing fees follow the published USCIS schedule. The substantial cost is internal: the engineering, quality and management time needed to document what is genuinely proprietary and how the employee came to know it.
The evidence is built, not bought
Companies often expect the cost to sit with counsel, and then find that the work sits with their own staff. Someone has to identify the proprietary process precisely, retrieve training and validation records that may be on a shared drive nobody has curated, and describe technical material in language a non-specialist reviewer can follow. That is real time from people who are also running production. Budget it explicitly rather than treating it as free. Beyond that, allow for certified translation of French-language records, for the U.S. entity’s own operating costs, and for the possibility that a request for evidence will require a second round of the same internal work. Check current government fees against the published USCIS fee schedule before budgeting.
Hypothetical example: a soil-testing laboratory spends heavily on a glossy technical report before verifying that the U.S. project needs its proprietary method. Budget first for records that establish the real claim: translated corporate documents if needed, training files, contracts, and time from knowledgeable managers. The first review should distinguish costs that clarify the employer's distinctive process from presentation costs that merely repeat conclusions. Ask whether the assignment has a defined end point within the category's five-year limit. A less elaborate file with traceable internal evidence is often more useful than a long report that never identifies the method or the employee's actual role in it.