Ann: Greater Pluto Reserves and Resource Update, page-11

In isolation it's not the end of the world - a 10% downgrade to 2P is never welcome but these things do sometimes happen. By definition, there's a 50-50 chance that a 2P reserves number will decrease. This will lower the NPV of Pluto and result in a small downgrade to valuations.

A bigger issue is that WPL is starting to make a habit of reserves downgrades which is not going to inspire market confidence, especially as WPL are not very transparent around reserves at the best of times.

If WPL project reserves are consistently being downgraded that suggests a systemic over-optimism at reserves estimation will very much affect market values as analysts start to factor in downgrade risk for the rest of WPL's portfolio. Particularly for LNG projects which have fairly low rates of return and long payback periods. A 10% downgrade might be pretty a significant chunk of your total profit.