Exhibit 23

CONSENT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

We consent to the incorporation by reference in the Registration Statement (File No. 333-208272) on Form S-8 of the 401(k) Savings Plan of First Niagara of our report, dated June 27, 2017, relating to our audit of the financial statements of the 401(k) Savings Plan of First Niagara for the year ended December 31, 2016.

Respectfully Submitted,

/s/ Insero & Co. CPAs, LLP

Insero & Co. CPAs, LLP

Certified Public Accountants

Rochester, New York

June 27, 2017