First Bank: email security grade A

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First Bank, St. Louis, Missouri, is the 224th largest FDIC-insured US bank by total assets ($6.7bn). On 4 November 2026 the public email records of first.bank graded A: MX pass, SPF pass, DMARC p=reject, mail handled by Microsoft 365.

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 first.bank

Check	Result	What was published
MX	Pass	`10 first-bank.mail.protection.outlook.com`. Mail handled by Microsoft 365
SPF	Pass	`v=spf1 ip4:40.134.20.96 ip4:108.166.45.120 ip4:50.31.43.169 include:spf.protection.outlook.com include:spfhost.messageprovider.com -all`. DNS lookups: 2 of 10 allowed; ends -all
DMARC	Pass	`v=DMARC1;p=reject;pct=100;rua=mailto:dmarcadmin@FIRST.BANK`. Policy p=reject, applied to 100% of mail; reports collected (rua= set)
DKIM	Pass, not graded	Key found on selectors s1, s2 (of 10 common selectors tried)

Where First Bank ranks

First Bank is the 224th largest FDIC-insured US bank by total assets, at $6.7bn as reported to the FDIC (certificate 12229; St. Louis, Missouri). Among the 999 graded banks, First Bank ranks 167th by grade (ties broken by assets, larger first). In its asset band, $1bn to $10bn, it ranks 52nd of 846; among the 35 graded banks in Missouri, 2nd. 66% of its band and 57.1% of its state graded A.

What this means for the bank

The checker's own notes on each record:

MX, pass: 1 MX record. Replies have somewhere to land. Mail is handled by Microsoft 365.
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: about 2 of the 10 allowed. This count is an estimate.
DMARC, pass: Policy p=reject: receivers are asked to refuse mail that fails.
DMARC, info: Reports go to dmarcadmin@FIRST.BANK.
DKIM, pass: DKIM key found at s1._domainkey.first.bank, about 2048-bit RSA.
DKIM, pass: DKIM key found at s2._domainkey.first.bank, about 1024-bit RSA.

What this means if you sell to First Bank

First Bank receives mail through Microsoft 365, whose Exchange Online Protection checks every inbound message's SPF, DKIM and DMARC and scores the sender's reputation. A clean, warmed sending domain is the minimum; a failed check lands in junk or is dropped. 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 first.bank now for today's result. The FDIC's record of the bank is at BankFind, certificate 12229.

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 First 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