what are the big 4 accounting firms

The Big 4, Defined

The 'Big 4' refers to Deloitte, PricewaterhouseCoopers (PwC), Ernst & Young (EY), and KPMG — the four largest accounting and professional services networks on earth, each operating in over 150 countries with combined global revenue in the hundreds of billions of dollars.

They dominate one specific niche: statutory audits of large, often publicly traded companies. If a company is listed on a stock exchange, there's a decent chance one of these four firms signs off on its financial statements every year. Beyond audit, they run massive tax advisory, M&A, and management consulting practices.

• •Deloitte — largest by revenue, strong in consulting and audit
• •PwC — historically strong tax and deals practice
• •EY — major strategy and transaction advisory arm
• •KPMG — smallest of the four, still a global audit powerhouse

What They Actually Do (and Don't Do)

Big 4 engagements are built for enterprise complexity: consolidating financials across dozens of subsidiaries, opining on internal controls under SOX, structuring cross-border tax positions, or advising on billion-dollar acquisitions. Their client roster skews toward Fortune 500 companies, large private equity portfolios, and government bodies.

What they generally don't do is small-business bookkeeping, monthly close, or the granular reconciliation work an Amazon seller actually needs — matching FBA settlement deposits to bank transactions, allocating COGS by SKU, or untangling reserve holds. That work sits with bookkeepers, e-commerce-specialized accounting firms, and software built for the platform's mess.

Why Amazon Sellers Should Look Past the Big 4

Third-party sellers now account for more than half of the physical gross merchandise sold on Amazon, according to Amazon's own investor disclosures. That's a massive, fragmented population of businesses with a very specific accounting problem: reconciling deposit-based marketplace payouts, not audited financial statements. The Big 4 aren't built to serve that volume at that price point, and they wouldn't be cost-effective even if they were.

The real accounting complexity for sellers is elsewhere — multi-state sales tax exposure, inventory valuation across FBA and FBM, and reimbursement accuracy. Since South Dakota v. Wayfair, states can require tax collection based on economic nexus rather than physical presence, and nearly all states with a sales tax now have marketplace facilitator laws that shift collection duty onto platforms like Amazon, per the Sales Tax Institute's state-by-state tracker. Amazon largely handles remittance for marketplace sales, but sellers still need clean books to reconcile what was collected, prove nexus exposure on other channels, and file correctly where required.

None of that needs a Big 4 audit team. It needs a books setup — properly built in Amazon accounting in QuickBooks & Xero — that separates gross sales, fees, refunds, and reimbursements cleanly at the transaction level.

Who Should Actually Use a Big 4 Firm

There's a narrow case where a growing seller does interact with the Big 4: pre-acquisition due diligence when selling a large brand, or a quality-of-earnings audit demanded by a private equity buyer. If your business is being valued in the tens of millions and a buyer wants an independent audit trail, a Big 4 or similarly credentialed regional firm may get engaged for that specific transaction.

For everything else — monthly bookkeeping, tax prep, sales tax filings, FBA reimbursement tracking — sellers are far better served by e-commerce-focused CPAs, bookkeepers, or purpose-built software. BeanHawk exists precisely for that gap: turning Amazon's settlement chaos into clean, accountant-ready books without paying enterprise-audit rates for small-business problems.

Frequently asked questions

Do I need a Big 4 firm to file my Amazon business taxes?

No. Big 4 firms rarely take on small-business tax returns; they're structured for large corporate and audit engagements. Most Amazon sellers are far better served by a CPA or bookkeeper who specializes in e-commerce and understands settlement reports, COGS, and multi-state sales tax.

What's the difference between the Big 4 and a regular accounting firm?

Scale and client type. The Big 4 audit large public and multinational companies and run global tax/consulting practices; regular accounting firms and bookkeepers handle small-to-midsize businesses, including day-to-day reconciliation and filings most sellers actually need.

Will Amazon send me a 1099-K, and does that involve any of the Big 4?

Amazon issues 1099-Ks directly based on IRS reporting rules for third-party platforms; the threshold has been phased down in recent years rather than staying fixed, per the IRS. This is a routine tax-prep matter, unrelated to Big 4 audit services.

Does Amazon collect sales tax for me, so do I even need to worry about nexus?

Amazon collects and remits sales tax on most marketplace sales under state marketplace facilitator laws, but you can still have nexus obligations from other sales channels, inventory storage, or thresholds triggered under economic nexus rules established after Wayfair. Clean books make it far easier to prove where you do and don't owe.

When would a growing Amazon brand actually need Big 4-level accounting?

Typically only during a sale process — if a buyer or investor requires an independent quality-of-earnings audit before a large acquisition. Day-to-day, an e-commerce bookkeeper or accountant handling reconciliations, COGS, and reimbursement tracking covers what sellers need.