In an expansive sealing order, a Manhattan federal judge, citing “sensitive business information” related to Simpson Thacher & Bartlett, has sealed a letter filed by an adversary and ordered other documents in the case sealed or redacted as well.

The order arises out of a lawsuit brought by Boston Executive Search Associates, a recruiting firm that sued Simpson Thacher in December. The company claimed Simpson Thacher wrongfully refused to pay a $937,500 placement fee for helping it find and hire attorney Michael Torkin from Sullivan & Cromwell.