From: Rabbi Moshe Sofer
To: Werdein
The Chasam Sofer rules that conducting commerce on Shabbos by opening one's shop constitutes Torah-level Shabbos desecration, disqualifying the violator from shechitah, testimony, and oaths. A Jewish-gentile partnership may operate on Shabbos only under strict conditions. Writing in any script on Shabbos, including non-Hebrew script, carries liability for a chatas.
Source: Shu"t Chasam Sofer CM §195