Can an L-1B specialist help establish a U.S. office?

Yes, if the employee and businesses meet the L-1B requirements and the additional new-office conditions are established. The role must involve specialised knowledge; opening an office is not itself a specialised-knowledge qualification.

Show an operating plan

Document sufficient premises, ability to pay the employee and commence business, the qualifying relationship and the required foreign employment. Explain which launch tasks depend on the employee’s existing knowledge. USCIS initially limits new-office approval to one year, so the plan should be practical enough to support both the proposed assignment and later evidence of actual operations.

A specialist can be involved in establishing a new operation, and the case then has to show an operating plan rather than an intention. Establish what the business will actually do, over what period, with what resources and premises, and how the specialised work fits within it. The knowledge argument and the new-office evidence are separate strands that both have to hold: it is not enough to show that the employee's knowledge is specialised if the receiving operation is not credibly going to be doing business, and it is not enough to show a well-funded launch if the proposed work does not require the knowledge.

Confirm as well that the underlying requirements are met, since the qualifying relationship and the continuous year of employment abroad within the preceding three years apply regardless of the office's age.