Without doing detailed calculations, I think it's due to the fact that spod prices were still under $500/t as at 31 Dec 2020 (the time frame of the Annual Report), and therefore they derecognised the tax asset.
That's why they go on in the second paragraph that the entity has US$202M in carried forward losses to highlight the potential future tax offset from profit.
Recognition and derecognition of assets are normal for reporting purposes.
GXY Price at posting:
$3.61 Sentiment: Buy Disclosure: Held
