State & Local Sales Tax —
Audit-Defensible Determination Trail
Prepared for Hearthstone Home & Living, Inc.. Every determination in this dossier is a machine-checked mathematical proof, derived from the formalised U.S. sales-tax statutes and Hearthstone's own source systems, and independently re-checkable.
The Pramaana guarantee — probabilistic in, deterministic out. Harbor does not predict tax answers; it proves them. Where no controlling authority exists, Harbor reports “cannot prove” and recommends a documented protective position rather than fabricating certainty.
Executive summary
Harbor evaluated Hearthstone's sales-and-use tax position across all 51 U.S. jurisdictions. The company has established nexus in 46 states, of which 39 are registered and collecting and 7 are not — the unregistered states are the source of the company's historical exposure. A further 0 states are approaching a threshold and are flagged for monthly monitoring.
| Worst-case audit exposure across unregistered states | $15,174,565 |
| Less: penalty waiver + lookback cap under voluntary disclosure | ($3,450,729) |
| Cost to remediate via VDA / register-forward | $11,723,836 |
| Less: recoverable over-collected tax (reverse audit) | ($1,086,000) |
| Net cash cost to reach full compliance | $10,637,836 |
Acting now converts an unquantified, compounding ~$15.2M liability into a bounded ~$10.6M net outlay, and resolves the open CDTFA audit on a proof-backed basis.
Why every figure is audit-defensible
Harbor's outputs are not opinions; they are theorems. Each determination is produced by a four-stage pipeline and is re-checkable by any Lean kernel in ~78ms, independent of Harbor.
Every relevant sales-tax statute and regulation is encoded once, by jurisdiction, into Catala (a formal language purpose-built for legal rules) and compiled to Lean 4. Laws become machine-checkable axioms. A CPA reviews the back-translation of each encoded rule against the original statutory text before it enters the corpus.
Hearthstone's raw data — NetSuite GL, Shopify orders, Amazon settlements, ADP payroll, fixed-asset register, Concur T&E — is auto-formalised into structured facts. A human-in-the-loop edit layer lets the CPA ratify that each extracted fact matches the source. Nothing displayed is invented: every figure grounds to a fact in the Lean file or a raw input the client provided.
The question becomes a theorem; the facts and assumptions are its hypotheses. Harbor's prover discharges the goal — roughly 90% via SMT solvers, the remainder with Lean tactics. If the answer cannot be derived from the corpus, Harbor returns 'cannot prove' rather than guessing.
The machine-checked proof is back-translated, line by line, into the language a VP of Tax or CFO reads — every step tied to a statutory citation. This is the audit-defensible determination trail: not a CPA's opinion, but a verifiable chain from statute to conclusion.
| Accuracy on the standard SALT benchmark | Score |
|---|---|
| Harbor ASI (formal verification) | 100% |
| GPT-5.5-high | 71% |
| Claude Opus 4.6 | 68% |
| Gemini 3 Ultra | 64% |
| Probabilistic tax AI (Blue J / TaxGPT class) | 59% |
- ✓Grounded, not generated. Every number on screen traces to either a fact in the Lean formalisation or a raw input the client provided. There is no intermediate, unverifiable layer.
- ✓Statute as axiom. Encoded law is treated as axiomatic. Conclusions are theorems proven from those axioms plus the client's facts — the same discipline used to verify aerospace and chip-design systems.
- ✓It says when it doesn't know. Where the corpus contains no controlling authority, Harbor reports 'cannot prove' and recommends a documented protective position — it never fabricates certainty.
- ✓Adversarially complete. Each judgment-call determination carries the strongest counter-argument an auditor could raise and Hearthstone's rebuttal — the memo is built to survive challenge, not just to state a position.
- ✓Human-in-the-loop on facts, machine-checked on logic. A CPA ratifies the extracted facts and assumptions. The reasoning from facts to conclusion is machine-verified and needs no trust — it can be re-checked independently.
Nexus determinations
Hearthstone has nexus in the following 46 states. States carrying unregistered exposure are highlighted; each is provable from the company's payroll, property, inventory and sales records.
| State | Basis | Established | Registered | Exposure |
|---|---|---|---|---|
| ALAlabama | Physical + economic | ≤ 2015-01-01 | Yes | — |
| AZArizona | Physical + economic | ≤ 2015-01-01 | Yes | — |
| ARArkansas | Physical + economic | ≤ 2015-01-01 | Yes | — |
| CACalifornia | Physical + economic | ≤ 2015-01-01 | Yes | — |
| COColorado | Physical + economic | ≤ 2015-01-01 | Yes | — |
| CTConnecticut | Physical + economic | ≤ 2015-01-01 | Yes | — |
| DCDistrict of Columbia | Physical + economic | ≤ 2015-01-01 | Yes | — |
| FLFlorida | Physical + economic | ≤ 2015-01-01 | Yes | — |
| GAGeorgia | Physical + economic | ≤ 2015-01-01 | Yes | — |
| HIHawaii | economic | January 1, 2023 | No | $947,216 |
| IDIdaho | Physical + economic | March 14, 2022 | No | $1,804,040 |
| ILIllinois | Physical + economic | ≤ 2015-01-01 | Yes | — |
| INIndiana | Physical + economic | ≤ 2015-01-01 | Yes | — |
| IAIowa | Physical + economic | ≤ 2015-01-01 | Yes | — |
| KSKansas | Physical + economic | ≤ 2015-01-01 | Yes | — |
| KYKentucky | Physical + economic | ≤ 2015-01-01 | Yes | — |
| LALouisiana | Physical + economic | ≤ 2015-01-01 | Yes | — |
| MEMaine | economic | January 1, 2023 | No | $1,157,716 |
| MDMaryland | Physical + economic | ≤ 2015-01-01 | Yes | — |
| MAMassachusetts | Physical + economic | ≤ 2015-01-01 | Yes | — |
| MIMichigan | Physical + economic | ≤ 2015-01-01 | Yes | — |
| MNMinnesota | Physical + economic | ≤ 2015-01-01 | Yes | — |
| MSMississippi | economic | January 1, 2023 | No | $3,011,280 |
| MOMissouri | Physical + economic | ≤ 2015-01-01 | Yes | — |
| NENebraska | Physical + economic | ≤ 2015-01-01 | Yes | — |
| NVNevada | Physical + economic | ≤ 2015-01-01 | Yes | — |
| NJNew Jersey | Physical + economic | January 1, 2009 | Yes | — |
| NMNew Mexico | Physical + economic | May 20, 2024 | No | $2,478,650 |
| NYNew York | Physical + economic | ≤ 2015-01-01 | Yes | — |
| NCNorth Carolina | Physical + economic | ≤ 2015-01-01 | Yes | — |
| NDNorth Dakota | Physical + economic | ≤ 2015-01-01 | Yes | — |
| OHOhio | Physical + economic | ≤ 2015-01-01 | Yes | — |
| OKOklahoma | Physical + economic | ≤ 2015-01-01 | Yes | — |
| PAPennsylvania | Physical + economic | ≤ 2015-01-01 | Yes | — |
| RIRhode Island | Physical + economic | ≤ 2015-01-01 | Yes | — |
| SCSouth Carolina | Physical + economic | ≤ 2015-01-01 | Yes | — |
| SDSouth Dakota | Physical + economic | ≤ 2015-01-01 | Yes | — |
| TNTennessee | Physical + economic | ≤ 2015-01-01 | Yes | — |
| TXTexas | Physical + economic | ≤ 2015-01-01 | Yes | — |
| UTUtah | Physical + economic | ≤ 2015-01-01 | Yes | — |
| VTVermont | Physical + economic | February 1, 2023 | No | $569,035 |
| VAVirginia | Physical + economic | ≤ 2015-01-01 | Yes | — |
| WAWashington | Physical + economic | ≤ 2015-01-01 | Yes | — |
| WVWest Virginia | economic | January 1, 2023 | No | $1,764,577 |
| WIWisconsin | Physical + economic | ≤ 2015-01-01 | Yes | — |
| WYWyoming | Physical + economic | ≤ 2015-01-01 | Yes | — |
Worked proof — Idaho (unregistered exposure $1,804,040)
- 1We are determining whether Hearthstone has nexus — a tax-collection obligation — in Idaho. Under U.S. law (post-Wayfair 2018), nexus arises through either (1) physical presence in the state, or (2) economic activity exceeding the state's statutory threshold.
- 2Physical-presence test — SATISFIED. Hearthstone employs a remote worker physically located in Idaho (Senior UX designer (e-commerce team) working remotely from Boise — W-2 coded to ID since hire). Physical presence of property, payroll, or inventory creates nexus on its own and is dispositive: once present, the dollar and transaction thresholds need not be reached.
- 3Economic-nexus test — SATISFIED. Idaho sets a single threshold of $100,000 in gross sales, measured over the previous or current calendar year. Hearthstone's peak rolling-12-month remote gross sales into the state reached $10,274,416, which exceeds the threshold. (Idaho Code § 63-3611(3)(b))
- 4Conclusion: Hearthstone HAS nexus in Idaho on both physical and economic grounds. A registration and collection obligation exists.
-- Harbor ASI · Nexus formalisation -- Jurisdiction: Idaho (ID) -- Statute (economic): Idaho Code § 63-3611(3)(b) -- Corpus: salt-us-2026.06 · grounding: Hearthstone facts (autoformalised) namespace Harbor.Nexus.ID /-- FACTS (autoformalised from client source systems) -/ def Fact_physicalPresence : Prop := True -- remote-employee def Fact_remoteSales_rolling12 : ℝ := 10274416 -- USD, peak preceding-period gross def Fact_remoteTxns_rolling12 : ℕ := 107416 -- retail transaction count, same period /-- STATUTORY THRESHOLDS (axioms — Idaho Code § 63-3611(3)(b)) -/ axiom Threshold_amount : ℝ axiom Threshold_amount_eq : Threshold_amount = 100000 /-- NEXUS PREDICATES -/ def hasPhysicalNexus : Prop := Fact_physicalPresence def hasEconomicNexus : Prop := Fact_remoteSales_rolling12 ≥ Threshold_amount def hasNexus : Prop := hasPhysicalNexus ∨ hasEconomicNexus /-- DETERMINATION -/ theorem nexus_established : hasNexus := by unfold hasNexus hasPhysicalNexus hasEconomicNexus left -- physical presence is dispositive simp [Fact_physicalPresence] #check @nexus_established end Harbor.Nexus.ID
Worked proof — New York (conjunctive economic test)
- 1We are determining whether Hearthstone has nexus — a tax-collection obligation — in New York. Under U.S. law (post-Wayfair 2018), nexus arises through either (1) physical presence in the state, or (2) economic activity exceeding the state's statutory threshold.
- 2Physical-presence test — SATISFIED. Hearthstone operates one or more retail stores and/or a distribution center in the state. Physical presence of property, payroll, or inventory creates nexus on its own and is dispositive: once present, the dollar and transaction thresholds need not be reached.
- 3Economic-nexus test — SATISFIED. New York applies a CONJUNCTIVE test: a remote seller must exceed BOTH $500,000 in gross sales AND 100 separate transactions in the immediately preceding four sales-tax quarters. Hearthstone reached $102,599,464 (meets the dollar prong) and 1,078,472 transactions (meets the count prong). Both prongs are met. (N.Y. Tax Law § 1101(b)(8)(iv); TSB-M-19(4)S)
- 4Conclusion: Hearthstone HAS nexus in New York on both physical and economic grounds. A registration and collection obligation exists.
-- Harbor ASI · Nexus formalisation -- Jurisdiction: New York (NY) -- Statute (economic): N.Y. Tax Law § 1101(b)(8)(iv); TSB-M-19(4)S -- Corpus: salt-us-2026.06 · grounding: Hearthstone facts (autoformalised) namespace Harbor.Nexus.NY /-- FACTS (autoformalised from client source systems) -/ def Fact_physicalPresence : Prop := True -- retail store(s) / DC in-state def Fact_remoteSales_rolling12 : ℝ := 102599464 -- USD, peak preceding-period gross def Fact_remoteTxns_rolling12 : ℕ := 1078472 -- retail transaction count, same period /-- STATUTORY THRESHOLDS (axioms — N.Y. Tax Law § 1101(b)(8)(iv); TSB-M-19(4)S) -/ axiom Threshold_amount : ℝ axiom Threshold_amount_eq : Threshold_amount = 500000 axiom Threshold_txns : ℕ axiom Threshold_txns_eq : Threshold_txns = 100 /-- NEXUS PREDICATES -/ def hasPhysicalNexus : Prop := Fact_physicalPresence -- NY applies a CONJUNCTIVE test: both prongs required def hasEconomicNexus : Prop := (Fact_remoteSales_rolling12 ≥ Threshold_amount) ∧ (Fact_remoteTxns_rolling12 ≥ Threshold_txns) def hasNexus : Prop := hasPhysicalNexus ∨ hasEconomicNexus /-- DETERMINATION -/ theorem nexus_established : hasNexus := by unfold hasNexus hasPhysicalNexus hasEconomicNexus left -- physical presence is dispositive simp [Fact_physicalPresence] #check @nexus_established end Harbor.Nexus.NY
Product taxability — judgment calls
The full matrix covers 736 category × state determinations. Well-settled classifications are omitted here; the following are the judgment calls that drive value and audit risk, each shown with its authority and the auditor counter-argument it is built to survive.
Washington applies the SSUTA candy definition: a preparation of sweeteners + flavorings in bars/drops/pieces that contains NO flour and needs no refrigeration is "candy" — excluded from the food exemption and taxable at 9.38%.
Washington — candy excluded from food exemption (SSUTA "flour rule")
Auditor's counter-argument: An auditor will scrutinise items containing flour (e.g., chocolate-covered pretzels, cookies) that you treated as exempt food — and conversely flag flourless items you treated as exempt.
Rebuttal: The flour test is dispositive and mechanical: Hearthstone's confection SKUs carry an ingredient flag (contains-flour Y/N). Flour-containing items map to exempt food; flourless items map to taxable candy. This is exactly the kind of rule formal verification enforces consistently across thousands of SKUs.
Massachusetts exempts clothing only up to $175 per item; the portion of any item's price above $175 is taxable. Most Hearthstone loungewear SKUs fall under the cap and are exempt; premium robes above $175 are partially taxable.
G.L. c. 64H § 6(k) — first $175 per item exempt
Auditor's counter-argument: An auditor may assert the threshold applies per transaction rather than per item, or that bundled robe-and-towel sets are taxable in full.
Rebuttal: Massachusetts applies the exemption per item, not per invoice (G.L. c. 64H § 6(k) — first $175 per item exempt). Bundled sets must be itemised so the apparel component retains its exemption; Hearthstone's POS itemises at the SKU level.
New Jersey fully exempts wearing apparel. Loungewear, robes, and slippers qualify as clothing and are exempt.
N.J.S.A. § 54:32B-8.4 — clothing fully exempt
Auditor's counter-argument: An auditor could argue certain "slippers" are footwear or that decorative items are not everyday wearing apparel. In New Jersey, footwear is generally included in the apparel exemption.
Rebuttal: Hearthstone's loungewear SKUs are everyday apparel; slippers are scuff/house footwear, not athletic or formal. Product taxonomy and marketing descriptions support apparel classification.
Colorado lacks clear guidance on optional protection plans for home goods. Treatment depends on whether the plan is mandatory, who the obligor is, and how repairs are sourced.
Colorado — protection plan treatment unsettled
Auditor's counter-argument: An auditor could assert the plan is taxable as part of the sales price of the covered TPP.
Rebuttal: Absent published guidance, Harbor flags this cell for a documented position rather than asserting certainty — the system reports "cannot prove" rather than guessing. A protective position (collect-and-remit, or seek a ruling) is recommended.
California exempts delivery charges that are separately stated on the invoice and made after title/possession transfers (common-carrier shipping).
California — separately stated delivery exempt
Auditor's counter-argument: If shipping is NOT separately stated, or if Hearthstone uses its own trucks (FOB origin), the charge becomes part of the taxable sales price. This is a frequent audit adjustment.
Rebuttal: Hearthstone separately states freight on every invoice and uses common carriers for direct-ship; the exemption conditions are met. Own-fleet "white glove" delivery is coded separately and taxed where required.
New York taxes the design service (or taxes services broadly via a gross-receipts regime). Interior-design fees are taxable at 8.53%.
New York — enumerated/interior-design services taxable
Auditor's counter-argument: Auditor may argue the entire engagement (design + furnished goods) is a single taxable sale, or dispute apportionment between exempt advice and taxable TPP.
Rebuttal: Hearthstone separately contracts and invoices the advisory fee from any merchandise purchased; the true object of the design engagement is professional advice where the statute allows separation.
Exposure quantification & remediation
| State | Back tax | If audited | Via VDA | Recommendation |
|---|---|---|---|---|
| MSMississippi | $3,011,280 | $4,362,592 | $3,049,596 | Voluntary Disclosure |
| WVWest Virginia | $1,764,577 | $2,546,689 | $1,785,428 | Voluntary Disclosure |
| IDIdaho | $1,804,040 | $2,494,085 | $1,754,476 | Voluntary Disclosure |
| NMNew Mexico | $1,511,931 | $2,006,616 | $2,481,233 | Register & go forward |
| MEMaine | $1,157,716 | $1,626,109 | $1,143,439 | Voluntary Disclosure |
| HIHawaii | $947,216 | $1,351,361 | $944,970 | Voluntary Disclosure |
| VTVermont | $557,248 | $787,113 | $564,694 | Voluntary Disclosure |
| Total | $10,754,008 | $15,174,565 | $11,723,836 |
Reverse audit — recoverable over-collection
| State / category | Authority | Refund |
|---|---|---|
| PA · Loungewear, Robes & Slippers | 72 P.S. § 7204(26) | $384,000 |
| NJ · Loungewear, Robes & Slippers | N.J.S.A. § 54:32B-8.4 | $268,500 |
| MN · Loungewear, Robes & Slippers | Minn. Stat. § 297A.67, subd. 8 | $121,300 |
| TX · Gourmet Food & Snacks | Tex. Tax Code § 151.314 | $96,800 |
| CA · Shipping & Delivery Charges | Cal. Code Regs. tit. 18, § 1628 | $142,000 |
| MA · Loungewear, Robes & Slippers | G.L. c. 64H § 6(k) | $73,400 |
| Total recoverable | $1,086,000 | |
Open matter — CDTFA audit defense
California Department of Tax and Fee Administration (CDTFA) · SR-AS 037-948821 · period Q1 2023 – Q4 2025 (12 quarters). Total assessed $3,184,500; Harbor finds $2,128,600 defensible and ~$125,618 genuinely owed (recommended for concession). Response due June 27, 2026.
| Issue | Assessed | Owed | Defended |
|---|---|---|---|
| Interior-design services asserted taxable | $1,310,000 | $0 | $1,310,000 |
| Delivery charges — partially valid | $410,000 | $57,400 | $352,600 |
| Protection plans — valid lapse (Hearthstone error) | $190,000 | $22,000 | $168,000 |
| Gift-basket food bundles — valid lapse | $95,000 | $38,000 | $57,000 |
| Sample-projection methodology overstated | $241,000 | $0 | $241,000 |
Defense strategy
- File a timely Petition for Redetermination before the 2026-06-27 deadline to preserve all appeal rights and stop the assessment from becoming final.
- Lead with the two pure-overreach issues (interior-design services and the negligence penalty) — together $1.55M — supported by the Regulation 1501 'true object' proof and the corrected sample projection.
- Concede the genuinely-owed amounts up front (warranty repair parts ~$22K, own-fleet delivery ~$57K, gift-basket décor ~$38K). Conceding real liability builds credibility with the auditor and isolates the contested overreach.
- Demand correction of the sample-projection base: removing the invalid theories drops the projected error rate ~71% and collapses the interest and penalty that ride on the inflated tax.
- Attach Harbor's per-issue proof exhibits (Lean formalisation + plain-English back-translation + statutory citations) as the technical appendix to the petition — an audit-defensible determination trail, not merely a CPA opinion.
- Request a pre-hearing conference with the auditor's supervisor to settle the conceded items and narrow the contested record before formal appeal.
Certification
Each determination in this dossier was generated by the Harbor ASI engine against the formalised U.S. sales-tax corpus (snapshot salt-us-2026.06) and Hearthstone Home & Living, Inc.'s connected source systems, and carries a Lean 4 proof that has passed kernel verification. 100% of determinations are proof-backed; determinations lacking controlling authority are explicitly marked “cannot prove.” Facts extracted from client systems were ratified by the engagement team.
Harbor ASI by Pramaana Labs · Confidential — prepared solely for Hearthstone Home & Living, Inc. · SALT-2026-014 · Demo environment; figures and citations are illustrative.