So if the northern tenements were given away for nil...

So if the northern tenements were given away for nil consideration yesterday, there would have been no impact on price?

GXY must have paid something for the rights, so the right to extract lithium from those tenements (less risk / capex / etc.) could be factored in by the market. The transaction gave the market a firm value to update assumptions - so assuming no other changes due to price of lithium, etc., the share price increased due to:
1. Northern tenements: uplift of sale price - less value embedded in price
2. Southern tenements: uplift of valuation applying sale price metric (as a minimum as this resource is better than that sold) - less value embedded in price
3. uplift for risk reduction (subject to completing the sale)

Shorts are providing good buying opportunities. All those believers in GXY with views for a long term hold should welcome them at the moment.