What we monitor: CIS monthly returns

How PenaltyProof monitors the monthly CIS 19th deadline for CIS contractors.

What we track

PenaltyProof alerts on the monthly CIS return deadline — the 19th of each month — for companies configured as CIS contractors at /manage. The CIS monthly check is enabled by default (cis_alerts_enabled flag).

Alert stages (paid plans)

Alerts at 30, 14, 7, and 0 days before the 19th. The scheduler fast-exits on any day that is not one of those thresholds relative to the 19th. Overdue alerts fire after the 19th if no filing is detected.

Configuration required

CIS alerts only fire for companies where CIS monitoring is toggled on at /manage.

What we do not monitor

We do not verify whether the CIS return was accepted by HMRC or whether deductions were correctly applied. We do not track nil-return filing separately — we alert on the deadline regardless of whether the return is nil or not.

Cross-link

See /deadlines/cis-monthly-return-deadline for penalty and regime details.

Common questions

What is the CIS alert threshold?

Alerts fire at 30, 14, 7, and 0 days before the 19th of each month. The scheduler fast-exits on any day that is not one of those thresholds relative to the 19th.

What configuration is needed?

Toggle CIS monitoring on per company at /manage. Companies without CIS monitoring enabled receive no CIS alerts.

Does PenaltyProof alert on nil CIS returns?

We alert on the monthly 19th deadline regardless of whether the return will be nil. We do not track whether the filed return was nil or substantive.

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