NRV vs Market value

I seem to be reading all different things about the differences here.

I know that inventories under GAAP will be valued at the lower or carrying value or market value. Also, inventories under IFRS will be valued at the lower of carrying or net realizable value.

Can someone explain the differences between the two?

Thanks!

NRV is selling price less costs to sell.

IFRS values at lower of cost or NRV

GAAP is lower of cost or market where market is replacement cost – as long as replacement cost is between NRV and NRV minus profit margin. In the case where replacement cost is lower than NRV minus margin, market = NRV - margin. In the case where cost is > NRV, market = NRV