From: Rabbi Moshe Sofer
To: Rabbi Meir Randiger
The Chasam Sofer rules that where a Jew acts purely as a broker or agent for a non-Jewish buyer without taking ownership or physically handling non-kosher fish, and given the significant financial stakes, the arrangement is permissible. This permissibility rests on two converging leniencies: the Jew has no personal ownership or liability, and he does not handle or see the forbidden items. He engages extensively with whether the sechorah prohibition is Biblical or Rabbinic and whether employing a non-Jewish agent can circumvent it, ultimately rejecting the analogy to Shabbos partnership laws.
Source: Shu"t Chasam Sofer YD §105