What Documents Do Accountants Need from New Clients?

Starting a new client relationship requires gathering comprehensive information. The documents you collect at the outset determine how effectively you can serve the client going forward. This guide provides exhaustive reference lists organized by client type, making it an invaluable resource for accounting bookkeepers and accountants alike.

Bookmark this page and reference it during every new client onboarding. A complete document collection at the start prevents countless follow-up requests later.

Universal Requirements (All Client Types)

Identification Documents

Every client relationship should begin with proper identification verification:

Government-issued photo ID (driver's license or passport) for all owners, partners, and officers confirms identity and provides signature samples for comparison.

Social Security card or SSN verification letter confirms the identification number. Never rely solely on verbal confirmation of Social Security numbers.

For entities: EIN confirmation letter (IRS Form CP 575) or EIN verification letter establishes the business tax identification number.

Prior Year Returns

Previous tax returns provide essential context for ongoing work:

Federal tax returns for the prior two years (or since formation for newer entities) show how the client has been filing and what positions have been taken.

State tax returns for all applicable jurisdictions reveal multi-state obligations and filing history.

Any amended returns filed, along with the reasons for amendment, help you understand the client's tax history.

Extension requests filed, if any, indicate the client's typical timeline for document provision.

Professional Contacts

Gather contact information for the client's other advisors:

Previous accountant or tax preparer contact information allows you to request prior year files and clarify questions about historical treatment.

Attorney contact for business formation, estate planning, or other legal matters provides access to documents that may affect tax treatment.

Financial advisor contact for investment-related questions and cost basis information connects you to another source of relevant data.

Insurance agent contact for questions about policy details and coverage documentation.

Individual Tax Clients

Personal Information

Beyond basic identification, gather complete personal information:

Current address and any address changes during the tax year affect state filing obligations.

Date of birth for all household members is required for various credits and deductions.

Marital status and date of any change during the year affects filing status and standard deduction.

Dependent information including names, dates of birth, Social Security numbers, and relationship is essential for claiming credits.

Custody arrangements if applicable determine who can claim dependents.

Income Documentation

Comprehensive income documentation prevents surprises:

W-2 forms from all employers, including short-term or seasonal positions.

1099-NEC forms for any freelance or contract work performed.

1099-MISC for miscellaneous income including rent, royalties, or prizes.

1099-INT for interest income from banks and other financial institutions.

1099-DIV for dividend income from investments.

1099-B for proceeds from stock sales and other securities transactions.

1099-R for retirement distributions from IRAs, 401(k)s, pensions, and annuities.

SSA-1099 for Social Security benefits received.

Schedule K-1 forms from partnerships, S corporations, or trusts.

1099-G for state tax refunds or unemployment compensation.

Gambling winnings (W-2G) and loss records.

Rental income and expense records if applicable.

Alimony received (for agreements before 2019).

Any other income sources not covered above.

Deduction Documentation

Thorough deduction documentation maximizes client benefit:

Mortgage interest statements (Form 1098) for all properties.

Property tax bills or payment records for all real estate.

State and local income tax records including payments made and refunds received.

Charitable contribution receipts and acknowledgment letters for donations over $250.

Medical expense records including insurance premiums, out-of-pocket costs, and medical mileage.

Student loan interest statements (Form 1098-E).

Tuition payments (Form 1098-T) and education expenses.

Educator expense receipts for teachers and educators.

Home office measurements and expenses if claiming the deduction.

Business mileage logs if self-employed.

Health insurance premiums for self-employed individuals.

Special Situations

Life events require additional documentation:

Home purchase: closing statement (HUD-1 or Closing Disclosure), mortgage documents.

Home sale: closing statement, purchase records, improvement receipts for cost basis calculation.

Divorce or separation: decree, settlement agreement, alimony payment records.

Death of spouse: death certificate, estate documentation, inherited asset information.

New child: birth certificate, adoption papers, SSN application.

Foreign income or accounts: foreign tax payments, FBAR-relevant account balances.

Small Business Clients

Formation Documents

Business structure documentation is fundamental:

Articles of incorporation, partnership agreement, or LLC operating agreement establishing the entity structure.

Bylaws or operating agreement amendments if applicable.

Business license and any required permits.

State registration certificates.

DBA (Doing Business As) filings if using a trade name.

Financial Records

Complete financial records enable accurate preparation:

Year-end balance sheet showing assets, liabilities, and equity.

Year-end profit and loss statement summarizing income and expenses.

Bank statements for all business accounts for the full year.

Credit card statements for business cards for the full year.

Loan documents including statements showing year-end balances and interest paid.

Accounts receivable aging report showing outstanding customer balances.

Accounts payable aging report showing amounts owed to vendors.

Inventory records including year-end count and valuation.

Payroll and Employment

Employment-related documentation is extensive:

Payroll summary reports showing wages paid by employee.

Quarterly payroll tax returns (Form 941).

Annual payroll tax returns (Form 940 for FUTA).

W-2 and W-3 copies for all employees.

1099-NEC forms issued to contractors.

Employee benefit records including health insurance, retirement plan contributions.

Workers compensation policy and audit information.

State unemployment tax filings.

This information often comes from accounting and payroll software systems the client uses.

Asset Documentation

Asset tracking affects both financial statements and taxes:

Fixed asset listing including purchase dates, costs, and current depreciation schedules.

Documentation for any assets purchased during the year.

Documentation for any assets sold or disposed of during the year.

Vehicle records including business use percentage and mileage logs.

Leased equipment agreements.

Owner Information

Owner-specific documentation varies by entity type:

For partnerships: capital account records, distribution records, partner personal information for K-1 preparation.

For S corporations: shareholder stock basis records, distribution records, shareholder personal information.

For C corporations: shareholder records, dividend payment records, officer compensation details.

For all pass-through entities: owner Social Security numbers and addresses for information return preparation.

Corporate Clients

Additional Corporate Requirements

Corporate clients require additional documentation beyond small business basics:

Board meeting minutes documenting major decisions including officer compensation, dividend declarations, and significant transactions.

Shareholder meeting minutes for annual meetings and special resolutions.

Stock ledger showing ownership percentages and any changes during the year.

Intercompany transaction records for affiliated entity transactions.

Transfer pricing documentation for international operations.

Related party transaction details for disclosure requirements.

Executive compensation details including deferred compensation arrangements.

M&A and Restructuring

If applicable, gather documentation for major transactions:

Acquisition or merger agreements.

Asset purchase agreements.

Stock purchase agreements.

Due diligence materials provided or received.

Valuation reports.

Legal opinions on tax treatment.

Non-Profit Clients

Formation and Exempt Status

Non-profit documentation starts with exempt status verification:

IRS determination letter (Form 501(c)(3) or other applicable section).

Articles of incorporation with exempt purpose language.

Bylaws current version.

State charitable registration certificates if soliciting donations.

Governance Documentation

Non-profit governance requires specific documentation:

Board meeting minutes for the year.

Conflict of interest policy and annual disclosure statements.

Compensation studies or comparability data for executive compensation.

Board member and officer list with addresses and compensation.

Program and Financial

Non-profit financial documentation includes:

Program activity reports showing charitable activities.

Fundraising records including donor lists and solicitation materials.

Grant agreements received and reports submitted.

Grants made to other organizations.

Functional expense allocation methodology.

Trust and Estate Clients

Trust Documentation

Trust engagements require specific documents:

Trust agreement or declaration of trust.

Any trust amendments.

Beneficiary information including names, SSNs, and addresses.

Trustee information and any changes during the year.

Prior year trust tax returns (Form 1041).

Estate Documentation

Estate administration requires extensive documentation:

Death certificate.

Will and any codicils.

Letters testamentary or letters of administration.

Inventory of estate assets with date-of-death values.

Appraisals for real estate, business interests, and other assets.

Claims against the estate.

Distributions made to beneficiaries.

Organizing Your Document Request

Customizing by Client Type

Create template checklists for each client type you serve. Start with the relevant sections above and customize based on your specific practice needs.

For example, an individual checklist might be much shorter than what is listed if you primarily serve simple W-2 employees. A business checklist might need additional items specific to your industry focus.

Phasing Your Requests

Consider whether to request all documents at once or in phases. For complex clients, phased requests may be less overwhelming:

Phase 1: Identification and prior returns (immediately at engagement)

Phase 2: Income and financial statements (as they become available)

Phase 3: Supporting documentation and special items (before preparation begins)

Making It Easy

The best gift for accountants is a client who submits complete documents promptly. Help clients give you that gift by making submission easy:

Provide clear, specific lists tailored to their situation.

Offer multiple submission methods (portal, email, physical drop-off).

Acknowledge receipt promptly so clients know their submission succeeded.

Follow up quickly on missing items while engagement is fresh.

Conclusion

Comprehensive document collection at the beginning of a client relationship sets the foundation for quality service. The lists in this guide cover the major client types you are likely to encounter, but every practice will need to customize based on their specific focus and client needs.

Use this guide as a starting point, not an ending point. Develop your own checklists, refine them based on experience, and systematize your onboarding process. The investment in thorough upfront documentation pays dividends throughout the client relationship.

Complete documents mean better service, fewer surprises, and more satisfied clients. That benefits everyone involved.