Which situation allows the second buyer to claim ownership of a patent?

The situation in which the second buyer can claim ownership of a patent involves the recording of the assignment of rights. According to U.S. patent law, specifically 35 U.S.C. § 261, rights to a patent are typically granted to the first entity that records their assignment with the United States Patent and Trademark Office (USPTO). However, if a second buyer records their ownership within a specific timeframe and is unaware of the first buyer's claim, they can potentially establish priority for ownership.

In this case, the second buyer recording after three months could be significant depending on whether or not the first buyer recorded their title first. If the first buyer is not recorded within that timeframe, the second buyer can assert their claim. The fact that the second buyer is unaware of the first buyer’s claim indicates that due diligence wasn't done on their part to ascertain existing rights, but this lack of awareness does not negate their ability to claim ownership if they record correctly within the stipulated time frame, assuming no prior valid recording exists.

This aligns with the principle of good faith purchases and the common law concept of "notice" — if the second buyer was not aware of the first buyer recording and fulfills the requirement of recording their assignment, they can still be awarded ownership