Copies of the Independent Contractor's business cards and stationery.
Copies of any advertising that the Independent Contractor has done, including advertising in the Yellow Pages or White Pages business listing.
If the Independent Contractor is operating under a fictitious or assumed business name, a copy of the fictitious or assumed business name statement or application.
Copies of any business or professional licenses.
Certificates showing that the Independent Contractor has insurance, including general liability insurance (and workers' compensation insurance if the Independent Contractor has employees).
A copy of the invoice form that the Independent Contractor uses to bill for services.
If the Independent Contractor rents business space, a copy of the office lease.
If the Independent Contractor has employees, a document containing the Independent Contractor's unemployment insurance number and Employer Identification Number.
Copies of IRS Form 1099-MISC that other hiring firms have issued to the Independent Contractor.
If the Independent Contractor is a sole proprietor and will agree to hand them over, copies of the Independent Contractor's tax returns for the previous two years showing that the Independent Contractor has filed a Schedule C, Profit or Loss From a Business.