Cornerstone Bank: email security grade A

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Cornerstone Bank, Fargo, North Dakota, is the 624th largest FDIC-insured US bank by total assets ($1.9bn). On 4 November 2026 the public email records of cornerstone.bank graded A: MX pass, SPF pass, DMARC p=reject, mail handled by Mimecast.

Grade A. Nothing in the records will stop mail. Read by DNS on 4 November 2026; the records are shown as published.

What was found on cornerstone.bank

Check	Result	What was published
MX	Pass	`0 us-smtp-inbound-1.mimecast.com`, `0 us-smtp-inbound-2.mimecast.com`. Mail handled by Mimecast
SPF	Pass	`v=spf1 include:amazonses.com include:spf.protection.outlook.com include:us._netblocks.mimecast.com include:spf.cashedge.com include:spf.zixsmbhosted.com include:cornerstone-bank.spf.smtp25.com ip4:69.178.222.34 exists:%{i}._spf.mta.salesforce.com include:spf.fmwrdc.com a:outbd-pstfx.customercenter.net a:outbd3-pstfx.customercenter.net -all`. DNS lookups: 10 or more of 10 allowed; ends -all
DMARC	Pass	`v=DMARC1; p=reject; rua=mailto:don.haag@cornerstonebanks.net`. Policy p=reject; reports collected (rua= set)
DKIM	Pass, not graded	Key found on selectors selector1, s1, s2 (of 10 common selectors tried)

Where Cornerstone Bank ranks

Cornerstone Bank is the 624th largest FDIC-insured US bank by total assets, at $1.9bn as reported to the FDIC (certificate 13198; Fargo, North Dakota). Among the 999 graded banks, Cornerstone Bank ranks 421st by grade (ties broken by assets, larger first). In its asset band, $1bn to $10bn, it ranks 306th of 846; among the 13 graded banks in North Dakota, 9th. 66% of its band and 84.6% of its state graded A.

What this means for the bank

The checker's own notes on each record:

MX, pass: 2 MX records. Replies have somewhere to land.
SPF, pass: One SPF record, ending in -all (fail): mail from a server that is not on the list should be rejected.
SPF, info: DNS lookups: at least 10 of the 10 allowed. One more sending service could push it over. This count is an estimate.
SPF, info: The record uses SPF macros, which only resolve for a real message, so the lookup count is a floor.
DMARC, pass: Policy p=reject: receivers are asked to refuse mail that fails.
DMARC, info: Reports go to don.haag@cornerstonebanks.net.
DKIM, pass: DKIM key found at selector1._domainkey.cornerstone.bank, about 2048-bit RSA.
DKIM, pass: DKIM key found at s1._domainkey.cornerstone.bank, about 2048-bit RSA.
DKIM, pass: DKIM key found at s2._domainkey.cornerstone.bank, about 2048-bit RSA.

What this means if you sell to Cornerstone Bank

Cornerstone Bank routes inbound mail through Mimecast, a filtering gateway. Expect strict inbound filtering: a message from a sender whose SPF, DKIM or DMARC fails, or whose domain has little sending history, is unlikely to reach a person. Before you send, run your own domain through the email setup checker and publish a policy with the DMARC record generator. For how a bank buys, see the selling to banks playbook.

Check it live

The records above are from 4 November 2026. Run the same check on cornerstone.bank now for today's result. The FDIC's record of the bank is at BankFind, certificate 13198.

This page is one of 1,000 in the Bank Email Readiness Index Q4 2026, published 4 November 2026 and re-read every quarter; the next edition is due 2 February 2027. If you work at Cornerstone Bank and the records have changed, email moe@roimaxi.com and we will re-check and update this page.

ROI Maximizer is a trading name of M Ventures LTD, registered in England and Wales, company no. 15554493. Registered office: 4 Beau Street, Bath BA1 1QY, United Kingdom. moe@roimaxi.com