Corviniti/Local Services/Bookkeeping Services in Suffolk County
Local Services / New York / Suffolk County
Bookkeeping Services in Suffolk County
Books closed every month, Suffolk County sales tax filed on time, the MCTMT handled, and a year-end package your tax preparer works from directly, at a flat monthly price.
What it is. A CPA-led team keeps your Suffolk County books current every month: transactions categorized, every account reconciled, financial statements delivered on a fixed date, and New York filings supported.
Who it is for. Suffolk County small businesses that have outgrown do-it-yourself QuickBooks or a part-time bookkeeper: trades, medical and dental practices, restaurants, professional services, e-commerce, and startups.
Why a New York firm. Your books feed New York filings a national bookkeeper does not track: sales tax at the county rate and the MCTMT that Long Island employers owe once payroll passes the exemption. We keep them to that standard.
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.
The service is monthly and flat-priced: we categorize your transactions, reconcile every bank and credit card account, deliver financial statements on a fixed date, and keep the books ready for New York filings. Suffolk County collects 8.75 percent sales tax, and because Long Island is inside the transportation district, employers above the payroll exemption also owe the MCTMT, both of which the books have to reflect.
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 bookkeeping 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.
How it works
What a proper bookkeeping month looks like
Every month runs the same cadence: transactions categorized, every account reconciled, payroll booked, and financial statements delivered on a fixed date.
The monthly close cycle. Illustrative.
Long Island sales tax
Sales tax for a Nassau or Suffolk seller
Nassau collects 8.625 percent and Suffolk 8.75 percent, both include the MCTD surcharge, and clothing is handled differently than in the city.
Nassau and Suffolk sales tax essentials. Illustrative and not exhaustive.
This is for you if
You are behind on your books and a tax deadline, a lender, or a landlord is asking for financials.
You are doing your own QuickBooks at night and no longer trust the numbers it shows you.
You collect Suffolk County sales tax and are not certain the returns match the books.
You have employees and are not sure the MCTMT is being handled right.
What you get
Monthly close and financials Profit and loss, balance sheet, and cash flow, reconciled and delivered on the same date every month.
New York filings handled Sales tax filed and the MCTMT booked against your payroll and kept current.
Cleanup that stays clean Catch-up from bank records to a books-to-bank reconciliation, then a monthly cycle so the backlog never rebuilds.
Year-end tax package Statements, schedules, and 1099 detail your preparer files from, or we prepare the returns ourselves.
How We Help
What you get
A CPA-led monthly service for Suffolk County businesses, priced flat, with the Long Island tax detail handled.
Monthly close and financialsProfit and loss, balance sheet, and cash flow, reconciled and delivered on the same date every month.
New York filings handledSales tax filed and the MCTMT booked against your payroll and kept current.
Cleanup that stays cleanCatch-up from bank records to a books-to-bank reconciliation, then a monthly cycle so the backlog never rebuilds.
Year-end tax packageStatements, schedules, and 1099 detail your preparer files from, or we prepare the returns ourselves.
When companies bring us in
You are behind on your books and a tax deadline, a lender, or a landlord is asking for financials.
You are doing your own QuickBooks at night and no longer trust the numbers it shows you.
You collect Suffolk County sales tax and are not certain the returns match the books.
You have employees and are not sure the MCTMT is being handled right.
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
Monthly bookkeeping and reconciliations
Most small business books fail in two places: transactions categorized wrong, and accounts that never get reconciled. Both compound until a loan application or a tax deadline forces the question.
How we handle it
We run your books on QuickBooks Online or Xero on a monthly cycle: every transaction categorized against a chart of accounts built for your business, every bank, credit card, and loan account reconciled to the statement, and payroll booked correctly, including the employer taxes owners miscount as profit. You get a profit and loss statement, balance sheet, and cash flow summary on the same date every month, with a short note on what moved, and one batched question list rather than a drip of emails.
Behind on the books, or unsure a Suffolk County filing is right? Talk to a CPA before the next deadline, not after it.
Sales tax is the state's money sitting in your account, and Long Island adds a payroll tax upstate businesses skip. Getting either wrong is where the penalties come from.
How we handle it
We set the books so sales tax posts to a liability, not income, and reconcile it to what the returns remit. Suffolk County collects 8.75 percent, made of the state's 4 percent, the county's 4.375 percent, and the 0.375 percent MCTD surcharge, with clothing under 110 dollars exempt only from the state portion because the county still taxes its share. We file the quarterly returns, keep the certificates that support every nontaxed sale, and, because Long Island is inside the transportation district, track the MCTMT against your payroll so it is booked and paid rather than found in an audit.
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 do bookkeeping for contractors and the trades?
Yes, we work with contractors, electricians, plumbers, HVAC companies, and general construction regularly, including job costing, work in progress, and the New York capital-improvement sales tax rules the trades get audited on. We work with the field service and job management platforms these businesses use, including Jobber, ServiceTitan, Housecall Pro, and Buildertrend, and bring that activity into your QuickBooks Online books so job profit and payments reconcile every month.
Do you work with medical, dental, and therapy practices?
Yes, we work with dental offices, medical practices, and therapy and counseling groups regularly, including reconciling insurance deposits net of adjustments and clawbacks back to billed production and keeping provider compensation splits clean. We work with the practice management systems these offices use, including Dentrix, Eaglesoft, athenahealth, and Tebra, and bring that activity into your QuickBooks Online books so collections and payer deposits reconcile to what the providers actually billed.
Do you do bookkeeping for restaurants and cafes?
Yes, we work with restaurants, cafes, bars, and food trucks regularly, including merchant deposits net of processor fees, tips run through payroll, and prepared food taxed at the full rate. We work with the point of sale systems these businesses use, including Toast, Square, and Clover, and bring that activity into your QuickBooks Online books so daily sales tie back to the register and the sales tax return is right.
Do you do bookkeeping for e-commerce and retail businesses?
Yes, we work with online sellers, Shopify stores, and brick-and-mortar retailers regularly, including separating marketplace-collected sales tax from your direct sales and tracking nexus as you sell into other states. We work with the sales and payment platforms these businesses use, including Shopify, Amazon, Stripe, and Square, and bring that activity into your QuickBooks Online books so each channel's revenue, processor fees, and sales tax are recorded correctly.
Do you work with law firms and professional services?
Yes, we work with law firms, consultants, engineers, and agencies regularly, including unbilled work in progress, retainers, and the strict separation of attorney trust and IOLTA funds from operating cash. We work with the practice and billing platforms these firms use, including Clio, MyCase, and LawPay, and bring that activity into your QuickBooks Online books so trust balances, billings, and collections reconcile every month.
Do you do bookkeeping for real estate and property management?
Yes, we work with landlords, real estate investors, and property managers regularly, including a separate profit and loss per property, security deposits held apart from income, and depreciation schedules kept current. We work with the property management platforms these businesses use, including AppFolio, Buildium, and Yardi, and bring that activity into your QuickBooks Online books so each property's income, expenses, and owner draws stay clean.
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.
