From concern + -ing. The adjective and preposition follow from the verb.
Concerning Sentence Examples
He reiterated his concern for the utmost confidentiality concerning the location.
Arguments concerning contact with tip lines became heated as well.
I have heard of certain projects concerning... you know.
When Dean questioned her, she told of receiving a phone call concerning that same property some weeks earlier.
In September 1844 Calhoun, then secretary of state, sent Green to Texas ostensibly as consul at Galveston, but actually, it appears, to report to the administration, then considering the question of the annexation of Texas, concerning the political situation in Texas and Mexico.