What it is. Preparation and filing of your federal and New York business returns for Suffolk County businesses, plus the owner's personal return, by a CPA working from reconciled books.
Where the value is. The New York elections and Long Island specifics: the separate CT-6 S election, the pass-through entity tax, the MCTMT, and estimated taxes managed so the return has no surprises.
Why a New York firm. New York has its own forms and its own rules. A preparer outside them leaves the CT-6 election, the PTET, and the MCTMT on the table or gets them wrong for Suffolk County businesses.
Corviniti provides bookkeeping, accounting, and tax services to small businesses across Suffolk County, from Riverhead and Hauppauge to Huntington, Patchogue, Babylon, and the East End. Suffolk is the most populous county in New York outside the city, and it files under New York rules with the downstate MCTMT that upstate businesses avoid.
We prepare and file business returns for Suffolk County companies: the federal return and the matching New York return, plus the owners' personal returns. Long Island businesses file federal and New York returns only; there is no county or New York City business tax layer here. The value is in the elections and the MCTMT that upstate preparers handle and out-of-town ones miss.
Corviniti keeps books, plans tax, and files returns for Suffolk County businesses under one roof, led by a CPA with Big Four experience. The full Long Island tax detail behind this service is on our Long Island business tax page; what it means for Suffolk County is below.
This page sits under Corviniti Accounting in New York City, our New York headquarters. That page covers the full New York City and New York State picture, and links to the rest of our local coverage.
Which return
Which return does your business file
Each entity files a federal return and a matching New York return. The map, plus the calendar.
Business returns by entity type. Illustrative and not exhaustive.
PTET mechanics
How the New York PTET works
The pass-through entity tax, step by step: what happens without the election, what changes with it, and the calendar it depends on.
How the PTET works, with and without the election. Illustrative, not tax advice.
This is for you if
You need your business return filed and are not confident last year's was done right.
You elected S corp federally but never filed New York's CT-6.
You are a profitable pass-through and have never heard your preparer mention the PTET.
You have employees and want the MCTMT handled with the return, not forgotten.
What you get
Both returns filed The federal return and the matching New York return, tied to the books and each owner's K-1.
The elections that cut the bill The CT-6 S election and the PTET, elected on time and reconciled onto the personal returns.
The MCTMT handled The Long Island payroll and self-employment MCTMT tracked, booked, and filed with the return.
The owner's return, coordinated Prepared alongside the business return so the K-1, the credits, and the estimates line up.
How We Help
What you get
A CPA-led return preparation for Suffolk County businesses, priced flat, with the Long Island tax detail handled.
Both returns filedThe federal return and the matching New York return, tied to the books and each owner's K-1.
The elections that cut the billThe CT-6 S election and the PTET, elected on time and reconciled onto the personal returns.
The MCTMT handledThe Long Island payroll and self-employment MCTMT tracked, booked, and filed with the return.
The owner's return, coordinatedPrepared alongside the business return so the K-1, the credits, and the estimates line up.
When companies bring us in
You need your business return filed and are not confident last year's was done right.
You elected S corp federally but never filed New York's CT-6.
You are a profitable pass-through and have never heard your preparer mention the PTET.
You have employees and want the MCTMT handled with the return, not forgotten.
The Detail
The gaps, and how we close each one
Service 01
The businesses Suffolk County depends on
The books and tax work should fit the local economy. Here is what Suffolk County's looks like and why it shapes the work.
How we handle it
Suffolk County's small-business base spans healthcare, a deep research and technology cluster, agriculture, and tourism. Stony Brook University, Brookhaven National Laboratory, and Cold Spring Harbor Laboratory anchor a science economy, and the Long Island Innovation Park at Hauppauge, with roughly 1,300 companies, is one of the largest industrial and innovation parks in the country. Suffolk is also New York's largest agricultural county by market value, with the North Fork wine country and East End farms, while the Hamptons and the marine economy drive a sharp seasonal tourism trade. Many Suffolk businesses are trades, practices, and seasonal operators whose books carry inventory, job costing, agricultural exemptions, and the MCTMT that Long Island employers owe. We keep them in that shape.
Service 02
The New York S election, and why federal is not enough
A business that elected S corporation status federally often assumes New York agrees. It does not automatically, and the gap can mean the state taxing the company as a C corporation.
How we handle it
New York requires its own S election on Form CT-6, separate from the federal Form 2553. We confirm your New York S status, file the CT-6 where it is missing, and make sure the election, the reasonable owner salary, and the distribution treatment line up on the return. If a prior year was filed on the wrong assumption, we flag it before the state does.
Unsure your last return got the New York elections and the MCTMT right? Have a CPA review it before the next filing.
Two of the biggest items for a Suffolk County business are the pass-through entity tax, which lives outside the normal return, and the MCTMT that Long Island owes but upstate does not.
How we handle it
We model whether the PTET pays under the current SALT cap, make the election online by the March 15 deadline (no extension), and reconcile the credit onto each owner's personal return. Because Long Island is inside the transportation district, we also handle the MCTMT for employers and the self-employed version for owners over the earnings threshold, so neither is forgotten at filing.
Service 04
Suffolk County and New York resources for owners
The registrations and filings Suffolk County owners ask about most are spread across state and county offices, each with its own rules.
Do you prepare returns for contractors and the trades?
Yes, the business return and the owner's. The items that decide a contractor's tax: the accounting method for long jobs (cash, accrual, or percentage-of-completion), work in progress on the return, the New York capital-improvement versus repair sales tax split, Section 179 and bonus depreciation on vehicles and equipment, and the S corporation and PTET elections for a profitable shop.
Do you prepare returns for medical and dental practices?
Yes, for the practice and its owners. The items that matter at practice income levels: entity choice (an S corporation is common), reasonable owner compensation, equipment depreciation, retirement-plan contributions that shelter high income, and the PTET election modeled per owner.
Do you prepare returns for restaurants and cafes?
Yes, for the business and its owners. The items that matter: the FICA tip credit on the employer payroll tax paid on reported tips, which is real money most preparers skip, Section 179 and bonus depreciation on equipment and build-out, cost of goods sold, and a return that reconciles to the sales tax you filed.
Do you prepare returns for e-commerce and retail sellers?
Yes, for the business and its owners. The items that matter: inventory and cost of goods sold accounting, sales tax nexus across states and the marketplace facilitator rules, fulfillment and home-office treatment, and the entity and PTET elections as the business scales.
Do you prepare returns for law firms and professional services?
Yes, for the firm and its owners. The items that matter: the cash versus accrual method, client trust funds kept out of income, partner and shareholder compensation, the PTET election that is often a partner group's largest lever, and the qualified business income deduction limits that apply to specified service businesses at higher incomes.
Do you prepare returns for real estate investors?
Yes, for investors, landlords, and property managers. The items that matter: depreciation and cost segregation to accelerate deductions, the passive activity loss rules and the real estate professional status that can unlock them, 1031 like-kind exchanges, and per-entity returns when properties sit in separate LLCs.
Do you work with businesses across all of Suffolk County?
Yes, from Riverhead, Hauppauge, and Huntington to Patchogue, Babylon, and the East End wineries and seasonal businesses. The work is done remotely on QuickBooks Online or Xero, so the location does not change the service. What matters is that your books reflect the 8.75 percent Suffolk sales tax and the MCTMT that Long Island employers owe.
This page summarizes New York State tax rules for general information, and is not tax advice for your situation. Rates and thresholds change; confirm the current figures with the authority before you rely on them.
