The LIFO conformity rule states that:

Once a company adopts LIFO, it cannot change to another method.

A company that uses LIFO must also disclose what the ending inventory would have been had it used FIFO.

If a company has operations outside the United States, it must conform to the way LIFO is used outside the United States.

If a company uses LIFO for its operations outside the United States, it must also use LIFO for its operations within the United States.

If a company uses LIFO for tax purposes, it must also use LIFO for financial reporting purposes.