300 | Additional tax assessed

Industry

IRS / Tax

Canonical

/irs-tax/error-codes/300/

Last Updated

Feb 25, 2026

Summary

This code indicates that additional tax was assessed, often related to examination or review findings.

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What This Code Means

Code 300 reflects an additional tax assessment posted to the account, typically associated with examination results or formal adjustments. It indicates that liability increased following review. The code represents the official posting of additional assessed tax. It does not provide detail about the underlying reason beyond its association with review outcomes. The entry typically includes the assessed amount.

Where Users Usually See This Code

On IRS account transcripts
After examination or review procedures
In connection with examination-related codes

Why This Code Appears

Examination resulted in increased tax liability
Adjustments were made following review
Corrections were applied to reported income or credits
Compliance action resulted in assessment

What Typically Happens Next

Account balance increases
Notice codes may accompany the assessment
Payment activity or offsets may occur

What This Code Is Not

It is not a refund code
It is not a pending status
It does not confirm penalties beyond assessment entry

Troubleshooting Checklist

□ Review associated notice entries
□ Confirm total balance after assessment
□ Monitor for further adjustment codes
□ Consult official IRS resources if clarification is needed

Notes And Edge Cases

Code 300 often appears in examination contexts and may follow code 420. The amount posted reflects the assessed increase. Reviewing full transcript context is necessary to understand cumulative changes.

Related Codes

8 links

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