The thing that surprises most people about a New York residency audit is how little of it depends on what you tell the auditor.
Many people approach the process the way they would approach an income tax audit: produce the documents requested, answer questions truthfully, explain your situation, and trust that a reasonable presentation of the facts will carry the day. That model is the wrong one. By the time the New York Department of Taxation and Finance opens a residency file, they have already built a parallel record of where they believe you actually were. Your job is not to tell them where you were. Your job is to demonstrate that your version of the year matches the record they have independently constructed.
This post walks through what that record looks like — what New York auditors collect, where they get it, and how they use it. It is not legal advice and it is not a substitute for working with a specialist attorney. But it is a description of what is actually on the table when the Nonresident Audit Bureau opens a case.
The Nonresident Audit Bureau
Before getting to the evidence, it is worth understanding who is examining you.
The Nonresident Audit Bureau is a specialized unit within the New York Department of Taxation and Finance. It does not perform general income tax audits. Its sole function is identifying high earners who claim to have left New York and determining whether the claim is accurate. The bureau has been operating in its current form for decades. Its examiners are not generalists who happen to be working a residency case this quarter — they are residency specialists, often with ten or twenty years of experience doing nothing else.
This matters because the playbook is mature. The bureau has audited thousands of cases. It knows which patterns indicate a real move and which indicate a paper move. It has settled cases, won cases, lost cases, and learned from each. The institutional knowledge is deep, and it is brought to bear on every file.
The bureau’s selection process is also data-driven. Cases are not chosen randomly. They are flagged by income level, by the pattern of the residency change, by the presence of New York property and connections after the claimed move, and by anomalies in filing history. By the time an examiner is assigned, the file already includes the demographic and financial markers that justified opening it.
The Day Count Is the Spine
Every New York residency audit ultimately turns on two questions. The first is the domicile question: where is your permanent home, the place you intend to return to, the center of your life? The second is the statutory residency question: do you have a permanent place of abode in New York and spend more than 183 days in the state in the tax year?
The day count is the spine of both inquiries. Domicile is qualitative — a multi-factor weighing of where your life actually is. Statutory residency is quantitative — a hard 183-day threshold. Either alone, if it goes against you, produces full New York resident tax liability.
The auditor’s first job is to reconstruct your year, day by day. Not approximately. Not based on what you say. Day by day, from independent sources, with documentary evidence behind each entry.
Cell Phone Records
The single most powerful piece of evidence in a modern New York residency audit is cell phone tower data.
Mobile carriers log which towers each phone connects to throughout the day. Even when you are not actively using the phone, it is associating with the nearest cell tower. Modern records can place a phone within a specific tower zone — often a few square miles in urban areas, smaller in dense networks — for essentially every hour of every day.
New York auditors subpoena these records. The carrier produces them. They are then mapped onto a calendar, and the result is a near-continuous record of where your phone was every day of the tax year. If your phone was connecting to towers in midtown Manhattan on Tuesdays, that is documented evidence. If it was connecting to towers in Palm Beach on weekends, that is documented evidence. The auditor does not need you to confirm either fact.
The defense to cell tower data is generally not to dispute it — the records are usually reliable — but to explain it. Were you traveling? Was someone else carrying your phone? Was the phone left at the New York apartment while you were elsewhere? Each of these explanations is possible but each requires its own evidence. A pattern of “my phone was in New York but I wasn’t” is a difficult position to maintain across many days.
EZ-Pass and Toll Records
Every time you pass through a toll on the New York State Thruway, the George Washington Bridge, the Triborough Bridge, the Whitestone, the Throgs Neck, the Verrazzano, the Holland Tunnel, the Lincoln Tunnel, or any other tolled crossing, the time and location are logged. Same on the New Jersey Turnpike, the Garden State Parkway, the Mass Pike, the Merritt Parkway, and the rest of the regional toll network.
These records are routinely subpoenaed in residency audits. Frequent tolls on the Triborough Bridge build a picture of regular travel into Manhattan. Frequent tolls on the GW Bridge build a picture of regular travel between New York and points west. The dates and times are precise, and they correlate cleanly with cell phone records.
What auditors particularly look for is the cluster pattern — a week of tolls suggesting you were physically present, followed by a gap, followed by another cluster. Even people who genuinely spent most of the year in Florida often have more frequent New York toll activity than they remember. The records don’t lie about it.
Credit and Debit Card Transactions
Every transaction made with a payment card is timestamped and geolocated. A coffee at a Manhattan deli, a meal at a restaurant in Bridgehampton, a parking garage on the Upper West Side, a Whole Foods run in Greenwich, an Uber ride in midtown — each is a documented physical presence at a specific place on a specific day.
Auditors do not need to subpoena cards from every merchant. They request statements from the taxpayer directly as part of the document production, and they cross-reference patterns. Recurring transactions — a regular gym, a regular dry cleaner, a recurring lunch spot — are particularly telling because they establish daily and weekly routines.
People often underestimate how much their card data reveals. A Florida resident who uses an Amazon delivery to a Manhattan address every other week, or whose American Express shows weekly transactions at the same Upper East Side restaurant, is producing a record that contradicts the residency claim before the auditor has asked a single question.
Air Travel Records
Flight manifests, frequent flyer accounts, and airline records establish departure and arrival cities. If you flew JFK to PBI on a Friday and PBI to LGA on a Sunday, those flights are documented in multiple places — airline records, TSA records (in some cases), credit card statements, and email confirmations.
Auditors request the records of flights taken during the tax year and use them as both confirmation and as anchors for the broader day-count reconstruction. A flight establishes that on a specific date, you were physically in a specific airport. The days between flights are inferred from other evidence.
Private aviation is included. Charter records, flight logs from fractional ownership programs, and tail number tracking through public databases all show up in the analysis. The notion that flying private hides your travel pattern from auditors is incorrect. It often produces a more precise record than commercial travel does.
Doorman, Building Staff, and Concierge Interviews
This is the technique that consistently surprises people who learn about it for the first time.
New York auditors have, for years, conducted interviews with building staff at the New York residences of taxpayers under audit. Doormen, concierges, parking garage attendants, building managers, and superintendents are interviewed about how frequently they saw the taxpayer during the year in question.
These witnesses are generally cooperative — they have no incentive to protect a tenant they may barely know — and they are observant. Doormen at high-end Manhattan buildings know which apartments are occupied, which residents come and go, and which tenants the building staff sees on a regular basis. Their testimony is admissible and credible.
The defense to doorman testimony is generally not to dispute it but to provide context. Were you traveling for work? Were guests using the apartment in your absence? Were you spending nights elsewhere in New York? Each is possible but requires its own corroborating evidence.
The lesson many taxpayers draw from this is that if you intend to claim non-residency, your relationship with your New York building staff should reflect a person who is rarely there. That is a thin reed and the auditor knows it.
Family Connections
The domicile inquiry looks closely at where your immediate family lives — particularly your spouse and minor children.
If your spouse continues to live in the New York apartment year-round while you claim to live in Florida, that fact will be weighed heavily against your claim. The standard framing in the case law is that a married person’s domicile typically follows the spouse’s domicile, especially when minor children are involved. Auditors look at where the spouse votes, where the spouse’s driver’s license was issued, where the spouse banks, and where the spouse spends time.
If your children are in New York schools — public schools in particular, where residency is required, but also private schools where the address on file is in New York — that is treated as strong evidence that the family’s home is in New York. Auditors will ask for tuition records, address verification with the school, and information about who pays tuition.
The principle is straightforward: domicile is the center of your life. If your spouse and children’s life is centered in New York, the claim that your life is centered in Florida is difficult to maintain regardless of where you personally spend your nights.
Items “Near and Dear”
New York’s domicile case law has a specific doctrinal concept around personal possessions that is worth knowing.
The phrase that comes up repeatedly is items “near and dear” — the things that are irreplaceable, sentimental, or of unusual personal significance. Family photographs. Heirlooms passed down through generations. Original art. Wedding mementos. Important family documents. Things that, if the house burned down, you would be devastated to lose.
Auditors ask, in interviews or in document requests, where these items are kept. The premise is that people store the things they care about most at the place they consider home. If your family’s irreplaceable items are in the New York apartment, that is treated as evidence that your real home is in New York. If they are in the Florida house, that supports the Florida claim.
This is a softer evidentiary category than cell phone data, but in close cases it can be decisive. Where you put your things tells the auditor where you live in a way that does not depend on your testimony.
The Comparative Home Analysis
When a taxpayer has homes in both New York and Florida, auditors compare them directly.
The analysis includes:
Size and value. A 4,000-square-foot Manhattan apartment compared to a 2,200-square-foot Florida condo invites the conclusion that the larger residence is the primary home.
Length of ownership. A home owned for twenty years versus a home purchased two years ago often suggests where roots actually run.
Use of the property. Photos, furnishings, personal effects, and the general character of the home factor in. A New York home with closets full of clothes, photos on the walls, and a fully equipped kitchen reads differently than one that has been emptied to look like a pied-à-terre.
Family use. Where the family gathers for holidays, where children’s bedrooms still exist, where major life events are celebrated — all of it is considered.
This comparative analysis does not, by itself, determine the case. But it is one of the most heavily weighted factors in the multi-factor domicile inquiry, and it is one auditors consistently emphasize.
Bank Accounts and Financial Activity
Auditors review bank account activity to identify location-based patterns. ATM withdrawals, in-person teller transactions, and recurring local-merchant transactions all establish physical presence.
The location of your primary banking relationships matters as well. A New York-headquartered private bank with a New York-based banker, who has been your private banker for fifteen years, factors into the domicile analysis even though banking is not by itself dispositive. Florida residents typically establish Florida banking relationships, including a primary checking account at a Florida branch, even if they retain their main investment relationships elsewhere.
The auditor will look at where checks are deposited, where wires are initiated from, and what address the bank shows on file. None of these is dispositive alone. All of them together build a picture.
Social Media and Public Information
Auditors look at publicly available information. They check Instagram for tagged locations. They check LinkedIn for stated location. They look at Facebook check-ins. They review Twitter activity for evidence of presence at specific events.
The amount of useful evidence an auditor can collect from public social media has grown substantially in the last decade. A photo posted from a Manhattan gallery opening on a Wednesday night when you claimed to be in Boca Raton is exhibit A. A LinkedIn profile that still lists New York as your location is a comment in the audit file.
Photo metadata is also reviewed in some cases. EXIF data on photos provided as evidence by the taxpayer can include GPS coordinates and timestamps. If you provide a photo as evidence that you were in Florida on a particular day and the photo’s metadata says it was taken in Tribeca, that hurts more than no photo at all.
Doctor, Dentist, and Veterinary Records
Routine medical care is one of the most consistent markers of where a person actually lives.
If you continue to use the same New York doctors and dentists you’ve used for twenty years, and you have not established equivalent relationships in Florida, that pattern is read as evidence that New York remains your home. Auditors will ask for the names of your medical providers and may request records to establish dates of visits.
Veterinary records are part of the same analysis. Where do you take your pets? People typically board, treat, and care for their pets where they live. A long-standing relationship with a New York veterinarian, with no equivalent Florida relationship, is a small but real data point.
Club Memberships and Religious Affiliation
Country clubs, social clubs, athletic clubs, and similar memberships establish ongoing community connections. Long-standing memberships at New York clubs that remain active after a claimed move are factors auditors consider.
The same is true of religious institutions. Where you attend services, where you tithe, where significant life events have been observed, are all part of the qualitative picture of where your community is.
Resigning or transferring memberships is not always practical, and the rules generally do not require it. But the auditor will note the connections that remain, and a pattern of unchanged community ties weighs against the claim that life has actually moved.
The Audit Conversation Itself
If a case progresses to interviews, the conversation is structured and detailed. Auditors are trained interviewers who know how to elicit specific factual answers without leading the witness.
Typical questions include:
- Where did you spend the night on December 31?
- When you arrive in New York, what is the first thing you typically do?
- Who is your primary care physician? When did you last see them?
- Where do you keep your most important personal possessions?
- When you say “going home,” which house do you mean?
The questions are deliberately concrete. Vague answers are followed up with specific ones. The answers are recorded and become part of the file.
This is not a hostile process in tone — auditors are generally professional — but it is rigorous. Inconsistencies between interview answers and documentary evidence are noted and weighed.
The Practical Lesson
The unifying theme of every category above is that New York auditors do not depend on your version of the year. They construct an independent record from sources that exist whether or not you cooperate, and they evaluate your residency claim against that independent record.
The implication for taxpayers is straightforward: the evidence you build during the year is more important than the explanation you construct after the audit notice arrives. A contemporaneous, GPS-verified day record that aligns with the independent evidence the auditor will assemble is the strongest possible defense. A reconstructed narrative built from credit card statements and old calendars three years after the fact is the weakest.
The day count is the single most important fact in most residency cases. It is also the easiest part to handle correctly, if you commit to it before the audit notice arrives.
Where Southbound Fits
Southbound is built around exactly this problem.
The app runs passively in the background on your iPhone, logging Florida days and non-Florida days using iOS’s significant-location-change system. No manual entries. No daily diary discipline required. The record builds itself as you live your life.
When an audit notice arrives, the record already exists. It is contemporaneous, GPS-verified, and exportable as a clean per-day log. It is the kind of evidence that does not contradict the auditor’s independent reconstruction, because it was built from the same kind of location data the auditor is working with.
The data lives in your own iCloud account. Southbound does not maintain a server-side copy of your location history. The record is yours, private, and produced only when you choose to produce it.
If the cost of a contested New York domicile audit can run into six figures of professional fees and seven figures of disputed tax, the cost of producing the documentation that closes the case quickly is meaningfully lower. The Departure Budget — the app’s central metric — also tells you in real time how many days you can still spend outside Florida and remain above the 183-day threshold. For people keeping a New York apartment, that number matters just as much as the Florida number.
The audit is not the moment to start your record. The year before the audit is.
This post is for general informational purposes only and does not constitute tax or legal advice. Residency audits involve complex, fact-specific legal questions. Work with a qualified tax attorney who specializes in New York domicile defense if you are facing or anticipating an audit.
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Published May 9, 2026