From: Rabbi Moshe Sofer
To: Rabbi Shaul HaKohen
The Chasam Sofer distinguishes between property saved by flight (no yeush occurred, so no hefker acquisition; partner may claim a division but is not believed with an oath without witnesses) and property rescued by direct confrontation (close to yeush, so the partner's oath is credible and he may acquire shares for his partners via the principle that a guardian's hand is like the owner's hand). In doubt, existing possession governs and the property is divided equally among all partners.
Source: Shu"t Chasam Sofer CM §100