Blame it on Mighty River Power's plunging share price. Blame it on Labour's and the Greens' plans to intervene in the wholesale electricity market.
Those two factors have blown a hole in National's hopes of building a "shareholders' democracy" where citizens would lean more to the right politically because they would have a stake in privatised companies.
More than 420,000 New Zealanders expressed an interest in buying shares in Mighty River Power. Some 113,000 got around to opening their chequebooks to do so.
The number applying for shares in Meridian Energy, the second state-owned power generator to be put up for partial sale, is nearly half that at about 62,000. And only 16,000 of them are first-time investors.
Fortunately for National demand was such that a fewer number of investors sought bigger parcels of shares, thereby avoiding breaching self-imposed limits on foreign ownership.
However, the Government is now going to be really pushed in meeting its target of raising between $5 billion and $7 billion in proceeds from its partial privatisation programme. It may well struggle to be even within the bottom end of that range.
Final judgment on the success or otherwise of the policy thus cannot be made yet. Much still hangs on how much is raked in from the two remaining companies in the asset sale basket - Genesis Energy and Air New Zealand.