What are common mistakes on Form 8962 that prompt IRS notices or CP messages?

1. Missing Form 8962 when APTC was paid — automatic e‑file rejection

If IRS records show APTC was paid for the taxpayer, the return will reject electronically under business rule F8962‑070 unless Form 8962 is attached or an “ACA Explanation” is provided; the agency explicitly instructs filers to include Form 8962 when anyone on the return enrolled through a Marketplace and received APTC ^{[1] [2]}. Third‑party reporting and prior IRS practice mean returns that omit 8962 are a primary trigger for immediate system flags and notices ^[4].

2. Mismatches between Form 1095‑A and entries on Form 8962

A frequent notice reason is a data mismatch: the Marketplace’s Form 1095‑A information in IRS databases must reconcile with the taxpayer’s Form 8962 entries, and discrepancies — from premium amounts to who was covered — prompt processing delays and requests for correction ^{[5] [6]}. The IRS and software vendors report that when the 1095‑A and 8962 don’t line up, returns are either rejected or pulled for correspondence ^{[5] [4]}.

3. Blank or improperly allocated monthly entries in Part II

Leavers or zeros not explicitly entered in the monthly allocation rows of Part II are a common technical cause of notices; taxpayers and tax‑prep tools have seen cases where leaving months blank (instead of entering zeros) or misallocating family members across months triggers IRS flags because the agency expects a complete month‑by‑month reconciliation ^[3]. Automated analyses from preparer forums and customer reports show software can silently omit these zero entries, creating a mismatch with IRS records ^[3].

4. Using an original instead of a corrected Form 1095‑A

When a corrected Form 1095‑A is issued, the IRS instructs filers to use the corrected version to compute the premium tax credit and not the original; failure to substitute corrected data can lead to reconciliation errors and subsequent notices ^[7]. The instructions explicitly warn that relying on an earlier, uncorrected 1095‑A for the same policy will delay processing ^[7].

5. Incorrect income estimates and household composition errors

Overly optimistic or inaccurate household income estimates and mistakes about who is claimed in the household (spouse, dependents) cause the PTC reconciliation to shift materially; common resources note that omitted household income, inaccurate income projections, or wrong dependent status often produce IRS adjustments, penalties, or requests for documentation ^{[8] [9]}. Practitioners warn that these are not just math errors but factual differences that change eligibility for the credit ^[8].

6. Data entry and identifying‑information mismatches

Beyond premium numbers, mismatches in identifying information — for example, SSNs or name fragments tied to dependents or enrollees reported on marketplace forms — can create system rejects or notices as the IRS crosschecks multiple databases ^[6]. E‑file reject guidance and vendor support materials flag SSN/ name mismatches and other control‑number errors among the common technical triggers ^{[6] [2]}.

7. How the IRS directs correction and where hidden pitfalls lie

The IRS guidance allows refiling with corrected Form 8962 or attaching a PDF “ACA Explanation” and supporting 1095‑A documentation if a filer believes 8962 is unnecessary; but practical pitfalls exist — tax software, missed zeroes, or reliance on an uncorrected 1095‑A can obscure the true error until the IRS contacts the filer ^{[1] [7]}. Advisors and forum reports underscore that while automated rejections protect IRS processing, they also surface software and communication failures between Marketplaces, preparers, and taxpayers ^{[3] [4]}.