What it is. A CPA-led accounting service for Nassau County owners: monthly financials you can act on, entity and New York tax planning, the S election and PTET handled, and a person to call before decisions.
Who it is for. Nassau County businesses past the startup stage that need more than clean books: a profit number they understand, a tax bill managed before year-end, and a CPA to call before decisions.
Why local knowledge. New York has levers a federal-only accountant misses: the separate CT-6 S election, the pass-through entity tax, and the MCTMT that Long Island employers owe. They change the entity math for Nassau County owners.
Corviniti provides bookkeeping, accounting, and tax services to small businesses across Nassau County, from Mineola and Garden City to Hempstead, Great Neck, Hicksville, and Long Beach. Nassau anchors the western half of Long Island's economy, and it files under New York rules with the downstate MCTMT that upstate businesses avoid.
A small business accountant interprets the numbers, plans the tax before the year closes, and advises the decisions that turn on the financials. For Nassau County, that covers the same New York levers as the rest of the state, the S election and the pass-through entity tax, plus the MCTMT that upstate businesses skip.
Corviniti keeps books, plans tax, and files returns for Nassau 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 small business accountant page; what it means for Nassau 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.
Who does what
Bookkeeper, accountant, CFO: who does what
Three roles, three jobs. The bookkeeper records, the accountant interprets and plans, the CFO looks forward.
The three roles compared. Illustrative.
Entity choice
Choosing an entity in New York
Sole proprietor, LLC, or S corporation, driven by profit and self-employment tax, with the New York S election most owners miss.
Entity choice and the New York elections. Illustrative, not tax advice.
This is for you if
You have a bookkeeper but still cannot tell which parts of the business make money.
Your profit keeps surprising you, and the tax bill surprises you more.
You are not sure your entity is right, or whether New York recognizes your S corporation.
You want a CPA to call before decisions, not an hourly meter after them.
What you get
Financials you can act on A monthly package built around your business, with the metrics that drive it and a read on what moved.
Entity and tax planning The S election, the PTET, and the MCTMT modeled and managed for your numbers.
The elections handled The New York S election on CT-6 and the PTET made on time, with the credit reconciled.
A CPA to call A New York-licensed CPA who answers within one business day, at a flat monthly price.
How We Help
What you get
A CPA-led accounting relationship for Nassau County businesses, priced flat, with the Long Island tax detail handled.
Financials you can act onA monthly package built around your business, with the metrics that drive it and a read on what moved.
Entity and tax planningThe S election, the PTET, and the MCTMT modeled and managed for your numbers.
The elections handledThe New York S election on CT-6 and the PTET made on time, with the credit reconciled.
A CPA to callA New York-licensed CPA who answers within one business day, at a flat monthly price.
When companies bring us in
You have a bookkeeper but still cannot tell which parts of the business make money.
Your profit keeps surprising you, and the tax bill surprises you more.
You are not sure your entity is right, or whether New York recognizes your S corporation.
You want a CPA to call before decisions, not an hourly meter after them.
The Detail
The gaps, and how we close each one
Service 01
The businesses Nassau County depends on
The books and tax work should fit the local economy. Here is what Nassau County's looks like and why it shapes the work.
How we handle it
Nassau County's small-business base leads with healthcare, anchored by Northwell Health, the state's largest private employer, headquartered in New Hyde Park. Around it sit dense professional and financial services in Mineola and Garden City, retail and hospitality, the construction and real estate trades that come with some of the country's highest home values, and an aerospace and defense engineering legacy in Bethpage, where Grumman built the lunar module and Northrop Grumman still operates. Education is a real employer too, with Hofstra in Hempstead and Adelphi in Garden City. Many of these are professional practices, trades, and partnerships whose books have to carry job-level or practice-level detail and the MCTMT that Long Island employers owe. We keep them in that shape.
Service 02
Entity choice and the New York S election
The entity decision drives self-employment tax and how New York taxes the business, and a federal-only analysis misses the New York step most owners skip.
How we handle it
Above a certain profit, an S election can cut self-employment tax, but it adds payroll and a reasonable-salary requirement, and New York requires its own S election on Form CT-6, separate from the federal Form 2553, which the state does not grant automatically. We model the actual savings for your numbers and file both elections where it makes sense.
Not sure your entity still fits, or whether the MCTMT is handled? Model it with a CPA before the next election deadline.
The pass-through entity tax is one of the biggest levers for a profitable Nassau County pass-through, and it is the one most commonly missed because it follows a strict separate calendar.
How we handle it
We model whether the PTET pays under the current federal SALT cap, roughly 40,000 dollars through 2029 with a phase-down for high earners. It pays New York tax at the entity level, where it stays federally deductible, and gives owners a credit on their personal returns. It is elected online by the March 15 deadline, which has no extension, and we reconcile the credit onto each owner's return so the deduction converts into cash saved.
Service 04
Nassau County and New York resources for owners
The registrations and filings Nassau County owners ask about most are spread across state and county offices, each with its own rules.
Yes, and past the monthly books. We track costs by job and carry work in progress correctly so you know which jobs made money, manage the New York capital-improvement sales tax split that gets the trades audited, and plan the S corporation and PTET elections that fit a profitable shop. We work with the systems you run, including Jobber, ServiceTitan, and Buildertrend.
Do you work with medical, dental, and therapy practices?
Yes. We reconcile insurance collections net of adjustments back to billed production, keep provider compensation splits clean, and plan the entity, equipment, and retirement-plan choices that lower the tax on a high-income practice. We work with the practice systems you run, including Dentrix, Eaglesoft, and Tebra.
Do you work with restaurants and cafes?
Yes. We track prime cost, food and labor as a share of sales, run tips and tip credits correctly through payroll, keep sales tax on prepared food right, and watch the margins that decide whether a location works. We work with the point of sale systems you run, including Toast, Square, and Clover.
Do you work with e-commerce and retail businesses?
Yes. We separate marketplace-collected sales tax from your direct sales, track inventory and cost of goods sold so gross margin is real, and monitor economic nexus as you grow into new states. We work with the platforms you run, including Shopify, Amazon, Stripe, and Square.
Do you work with law firms and professional services?
Yes. We handle unbilled work in progress and retainers, keep attorney trust and IOLTA funds strictly separate from operating cash, and plan the S corporation and PTET elections that fit a partner group's income. We work with the platforms you run, including Clio, MyCase, and LawPay.
Do you work with real estate and property management?
Yes. We keep a profit and loss per property, hold security deposits separate from income, keep depreciation current, and plan the cost segregation, 1031 exchange, and entity moves that drive real estate returns. We work with the platforms you run, including AppFolio, Buildium, and Yardi.
Do you work with businesses across all of Nassau County?
Yes, from Mineola and Garden City to Hempstead, Great Neck, Hicksville, and Long Beach. The work is done remotely on QuickBooks Online or Xero, so where in Nassau you sit does not change the service. What matters is that your books reflect the 8.625 percent Nassau 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.
