资产负债表外项目，顾名思义是指资产负债表或附注中没有反映出来的项目。这些项目多数跟资产和债务有关。它可能涉及租赁、附属公司或或有负债（contingent liability）的法律责任，如信用证（letter of credit）。它还涉及贷款承诺、 期货、远期合约和其他衍生工具。

有些公司可能有大量的资产负债表外的资产和负债。举例来说，金融机构往往提供资产管理（asset management）或经纪服务予其客户。资产（多数是证券）多数属于个别客户，而该公司为客户提供管理、托管或其他服务。该公司本身对资产并没有申索权，而对客户一些基本的受托责任。金融机构可能会在财务报告中，正式地列出资产负债表外项目；其会计报表，也可能归类在“管理下的资产”。

Off-balance sheet (OBS), or Incognito Leverage, usually means an asset or debt or financing activity not on the company's balance sheet.

Some companies may have significant amounts of off-balance sheet assets and liabilities. For example, financial institutions often offer asset management or brokerage services to their clients. The assets managed or brokered as part of these offered services (often securities) usually belong to the individual clients directly or in trust, although the company provides management, depository or other services to the client. The company itself has no direct claim to the assets, so it does not record them on its balance sheet (they are off-balance sheet assets), while usually has some basic fiduciary duties with respect to the client. Financial institutions may report off-balance sheet items in their accounting statements formally, and may also refer to "assets under management," a figure that may include on and off-balance sheet items.