Keep your EIN secure.
Just like an identity thief can wreak havoc on an individual through accessing their social security number, a business' Employer Identification Number is a key to committing corporate fraud. Ensure all documents with this number are secured or properly destroyed when no longer needed.
Just because a document is useless to you doesn't mean it has no value to an identity thief. Once you no longer need bank statements, receipts, or invoices, be sure to shred them to make your important information unusable in the hands of dumpster divers.
Store documentation offsite.
As a business, you have many service providers coming and going from your office space. When your files are stored offsite at a secure location, fewer people have access to your important documents. Choose a location that is monitored by closed circuit surveillance systems and ensures that all visitors are escorted by security staff.