How to interpret a negative relative Gibbs free energy (ΔGpbx)?

Hi all,

I’m just wondering on the best way to interpret negative relative Gibbs free energy (-ΔGpbx) values on an aqueous stability plot?

Wouldn’t a negative value mean the material in question is more stable than the pourbaix stable domain it is being compared to?

I’m sure i’m missing something obvious here. Happy for any advice on this!