Based on the search results, the Native American Graves Protection and Repatriation Act (NAGPRA) can impact private collectors and institutions in the following ways:

NAGPRA applies to any museum or institution that receives federal funding. This includes private universities, local government agencies, and even private collectors if they are part of a larger entity that receives federal funds.

NAGPRA requires these federally-funded entities to inventory and repatriate Native American human remains, funerary objects, sacred objects, and objects of cultural patrimony to lineal descendants, tribes, and Native Hawaiian organizations. This applies even if the items were legally acquired before NAGPRA was enacted.

The proposed changes to the NAGPRA regulations in 2023 aim to further expand the definition of what qualifies as a "sacred object" or "object of cultural patrimony", which could impact more private collections and institutions that were previously not considered subject to NAGPRA.

NAGPRA violations can result in civil and criminal penalties, providing a strong incentive for private collectors and institutions to comply with the law. The law has been used to recover culturally significant items from private collections.

However, NAGPRA does not apply to institutions outside the United States, so foreign private collectors may not be subject to the law's requirements.

In summary, NAGPRA has a significant impact on private collectors and institutions in the United States that receive any form of federal funding, requiring them to inventory, consult with tribes, and potentially repatriate Native American cultural items. The proposed regulatory changes aim to further expand NAGPRA's reach.

References:

1. https://culturalpropertynews.org/nagpra-major-changes-proposed-for-2023-to-native-american-repatriation-law/

2. https://www.federalregister.gov/documents/2010/03/15/2010-5283/native-american-graves-protection-and-repatriation-act-regulations-disposition-of-culturally

3. https://www.nps.gov/subjects/archeology/napgra.htm

4. https://nagpra.ucdavis.edu/resources

5. https://www.federalregister.gov/documents/2022/10/18/2022-22376/native-american-graves-protection-and-repatriation-act-systematic-process-for-disposition-and