Business Accounting & Advisory Services

Business Accounting & Advisory Services for Small Businesses

From Port Jefferson Station to St. James, O’Hara & Company CPA helps Long Island’s small and mid-sized businesses stay financially sound and growth-ready. With more than 30 years of hands-on experience, our accounting and advisory team delivers personalized, practical solutions—so you can spend less time on paperwork and more time running your business.

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Supporting the Numbers So You Can Grow the Business

We serve contractors, retailers, professionals, and nonprofit leaders across Suffolk County with accounting services that go beyond balancing books. Whether you’re just starting out or managing a growing operation, our team offers the tools and guidance to help you stay compliant, make informed decisions, and plan for sustainable growth.

Bookkeeping & Write-Up

We’ll handle your day-to-day numbers—monthly reconciliations, ledger maintenance, QuickBooks support, and catch-up bookkeeping for businesses that need to get back on track.

Payroll Management

From wage calculations to tax withholdings and quarterly filings, we manage payroll so your team gets paid and you stay compliant with IRS and NYS requirements.

 Outsourced CFO Services

Get executive-level financial strategy without the full-time cost. We offer part-time CFO guidance, cash flow forecasting, budgeting, and long-term planning.

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Forward-Looking Financial Advice for Every Stage

Whether you're preparing for expansion or just trying to boost profit margins, our business advisory services offer actionable insights. We help you build stronger budgets, understand your financials, and improve long-term viability with clear, CPA-backed guidance.

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Start Your Business the Right Way

Thinking of launching a new venture? We’ll help you choose the right structure (LLC, S-Corp, etc.), register with state and IRS authorities, and establish a clean bookkeeping foundation from day one.

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We Know Your Industry—And Your Pain Points

We’ve helped clients in construction, retail, healthcare, and professional services keep their books clean and compliant. For nonprofits, we offer IRS Form 990 preparation and fund accounting expertise.

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Business Taxes Without the Stress

We prepare and file business tax returns, help you manage sales tax, and provide year-round tax planning so you’re not scrambling at year-end. If you’ve got payroll tax issues or back taxes, we can help you work toward resolution.

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Stay Compliant with Sales Tax Filing

Sales tax laws in New York can be complex, with filing requirements that vary monthly, quarterly, or annually depending on your business size and industry. Our team ensures your sales tax returns are prepared accurately and filed on time with the state, so you avoid penalties and interest. We’ll also help you stay ahead of changing rules and rates across Suffolk County and Long Island.

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QuickBooks Done Right

Whether you use QuickBooks Online or Desktop, we provide training, setup, and ongoing support. From organizing your chart of accounts to running meaningful reports, we’ll help you get more from your accounting software.

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Independent Audits & Financial Reviews

For businesses requiring certified financial statements or independent reviews, we conduct thorough audits and reviews to ensure compliance and provide stakeholders with verified financial insights.