excess business holding rule for nonprofit

Just want to clarify if the excess business holding restriction only apply to private foundation or also public charity.
Thank you!

Sec 4943.

(a) Initial tax
(1) Imposition
There is hereby imposed on the excess business holdings of any private foundation in a business enterprise during any taxable year which ends during the taxable period a tax equal to 10 percent of the value of such holdings.

Thank you! That is my understanding too! Thanks