An expense will decrease the amount of assets or increase the amount of liabilities, and will reduce the amount of owner's or stockholders' equity.

For example an expense might:

1) reduce a company's assets such as Cash, Prepaid Expenses, or Inventory,

2) increase the credit balance in a contra-asset account such as Allowance for Doubtful Accounts or Accumulated Depreciation,

3) increase the balance in the liability account Accounts Payable, or increase the amount of accrued expenses payable such as Wages Payable, Interest Payable, and so on.