The Supreme Court dismisses a series of Telecom vs Vodafone cases relating to a controversial rural telecommunications levy paid to Telecom - but raises the possibility that Telecom rivals beyond Vodafone might have paid too much.

ABOVE: TSO charges for a typical year (July 2007 to June 2008). The Commerce Commission has blacked out part of Telecom's entry. The levy is determined by the commission, but rival telcos pay it directly to Telecom.

The Commerce Commission has been told by the High Court at Wellington to re-do its TSO (Telecommunications Service Levy) sums for the 2004/2005 and 2005/2006 years.

Communications Minister Steven Joyce has finalised his rural telecommunications plan.

As expected, it’s bad news for Telecom.

The company is to lose its long-time annual subsidy - the TSO Levy (formerly known as the Kiwishare levy) - for servicing so-called “commercially non-viable rural customers”.

Telecom immediately released a statement to the NZX saying Mr Joyce's decision could slice up to $56 million a year off ebitda for each of its 2011 (currently forecast at $1.77 billion), 2012 and 2013 financial years).

Vodafone New Zealand has lost its appeal to recoup $17.9 million it paid Telecom in historic determination costs as set by the Commerce Commission for the 2003 financial year.

ABOVE: TSO liabilities, July 2008 - June 2009. The TSO levy is used to subidise Telecom for the cost of providing voice and dial-up service to "commercially non-viable" rural customers (59,240 of them last year).

The Commerce Commission divvies up the TSO bill with a formula based around how much of each telco's annual revenue is drawn from activity that touches on Telecom's PSTN (public switched telephone network).