Tax Reference

State Tax & IRS Compliance

State income tax residency, SALT planning, remote work, IRS audits, penalties, and compliance procedures.
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State income tax can equal or exceed federal tax in high-rate states, and the residency rules are more aggressive than most people expect. The New York convenience of employer rule, the 183-day statutory residency trap, and the dual-resident problem all create real exposure. This section also covers IRS compliance - audits, penalties, and the procedures for resolving tax problems.

State Tax
Guide
State Income Tax Nexus
183-day rule, domicile vs. statutory residency, NY convenience rule, domicile change.
Guide
State Residency Planning
HNW domicile change, audit defense, near and dear test.
Guide
Remote Worker State Tax
Multi-state filing, withholding, convenience rule.
Guide
No Income Tax States
9 states, tradeoffs, planning considerations.
Guide
SALT Planning Guide
$40K cap, PTET elections, planning strategies.
Calculator
ACT 60 / Puerto Rico Estimator
PR resident tax savings under Act 60.
Guide
PTET: Pass-Through Entity Tax SALT Workaround
PTET federal framework (Notice 2020-75) and 36+ state regimes. OBBBA preserved PTET despite $40K SALT cap. State-by-state mechanics: NY irrevocable March 15 election (graduated 6.85-10.9%); California 9.3% with mandatory June 15 prepayment, extended through 2030; Connecticut converted mandatory→elective; Illinois made permanent Dec 2025. Resident credit vs income reduction models. Multi-state tiered entity complexity. §1361(b)(1)(D) single class of stock. QBI / §163(j) / §461(l) interactions.
IRS Compliance
Guide
IRS Audit Guide
DIF scoring, audit types, SOL, 90-day letter, Appeals, OIC.
Guide
IRS Payments Guide
Payment methods, installment agreements, EFTPS.
Calculator
Penalty Calculator
Failure to file, failure to pay, FTA abatement.
Guide
Tax Extension Guide
Form 4868, corporate extension Form 7004.
Guide
Tax Calendar 2026
All federal deadlines for individuals, businesses, trusts.
Guide
IRS Account Guide
IRS Online Account, transcripts, tax records.
Guide
IRS Appeals Process
30-day letter, CDP hearing §6330, CAP, equivalent hearing. Forms 12153, 12203, 9423. Post-Zuch update.
Guide
IRS Penalty Abatement
FTA (automatic for TY2025+), reasonable cause, RP 84-35 S-corp/partnership relief, Form 843 mechanics.
Guide
Form 2210 Underpayment Penalty
§6654 safe harbors (90% current / 100% prior / 110% AGI >$150K). Schedule AI annualization. Q1 2026 rate 7%, Q2 2026 6%.
Guide
Form 1040-X Amended Return
§6511 refund SOL (3yr/2yr). 7yr bad debt, 10yr FTC. E-file current + 2 prior tax years. December 2025 revision continuous use.
Guide
Form 8275 / 8275-R Disclosure
§6662(d)(2)(B) accuracy penalty defense. Reasonable basis vs substantial authority. §6694 preparer exposure. Rev. Proc. 2024-50.
Guide
§6672 Trust Fund Recovery Penalty
100% personal liability for responsible person who willfully fails to pay over withheld trust fund taxes. Form 4180 interview, Letter 1153(DO), Form 2751. NO statutory reasonable cause exception. Survives bankruptcy. Joint and several.
Additional Resources
Guide
Illinois Income Tax
4.95% flat rate; retirement income fully exempt; $4M estate tax.
Guide
New Jersey Income Tax
10.75% top rate; inheritance tax; ANCHOR property relief.
Guide
California FTB Tax Guide
13.3% top rate; FTB audit triggers; CA non-conformity.
Guide
Puerto Rico Act 60
4% capital gains; bona fide residency 183-day test.
Guide
NYC Unincorporated Business Tax
4% rate, $95K exemption, investment income excluded, 23% NYC resident credit.
Guide
SaaS Sales Tax
Wayfair nexus, taxability by state, B2B exemption certificates.
BREAKING
Cannabis & §280E
April 22 2026 rescheduling - state tax treatment independent of §280E change.
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