Data breach

Mercadien, P.C. CPAs

Location not known1 source

NotifiedMercadien, P.C. CPAs notified the California Attorney General of a data breach on 20 Oct 2026. The cause was not stated.

See it on the live map Am I affected?

Location not known.

First reported: 20 Oct 2026
Latest source: 20 Oct 2026

What is known

Confirmed

No confirmed figure

Claimed

No claimed figure

Data involved

Data types not stated

Cause

Cause not stated

Attack: 17 Sept 2025
Disclosed: 20 Oct 2026
First seen by Black Shard: 9 Nov 2026

Filings

California Attorney General20 Oct 2026Breach notice

Sources

California Attorney GeneralPrimary source20 Oct 2026California Attorney General breach notice sb24-631642

Status timeline

20 Oct 2026
California Attorney General, primary source
20 Oct 2026
Status: notified

What to do

If you have an account, change that password, and anywhere you reused it.
Turn on two-factor authentication, ideally an authenticator app or passkey, not SMS.
Expect phishing that uses your real details. Do not click links in messages about this incident; go to the company's site directly.
If payment cards were involved, watch statements and ask your bank for a new card.
If government ID or social security numbers were involved, consider a credit freeze.

Talk to our team 24/7 incident line: 1800 370 270

How sure we are

That it happened as stated 90%

The place 0%

1 independent source. Location not known.

Not known yet

Number of recordsData involvedWho did it

Update log

9 Nov 2026First seen.

Under attack? Call the incident line.

Black Shard's team can check your exposure, take a fix off your plate or step in on a live incident.

Talk to our team Breach response

24/7 incident line1800 370 270Call first, then work through the first-hour steps.