Spark, formerly known as Telecom, has bought a 26 per cent stake in Hawke's Bay-based telecommunications company NOW.
NOW CEO Hamish White said the stake from its competitor was a vote of confidence it was "on the right track" and would use proceeds of the sale towards its ongoing rollout of broadband and calling services in the lower North Island.
NOW has grown 40 per cent for each of the past two financial years.
"I see Spark's interest as a real show of confidence in NOW's proven ability to understand our local customers and give them the service they deserve," he said. "They appreciate our 'high service, high value' business model that ensures our customers get the most from their technology."
Founded in Hawke's Bay in 2002, NOW provides broadband and calling services to business and residential customers throughout Hawke's Bay, Wellington, Kapiti, Rotorua, Taupo and Whakatane.
A Tauranga and Hamilton office is planned for next year and NOW's Digital Concierge service, enabling optimum in-home internet connectivity, will continue to expand.
The investment means more Hawke's Bay jobs, with 60 new Now employees projected for the next 12 months.
Spark New Zealand chief financial officer Jolie Hodson would sit on the NOW board.
"We have invested in NOW New Zealand Ltd because it's a New Zealand-owned and operated ISP with ambitious growth plans and a proven ability to deliver for their customers in the regions," she said.
"We are excited to support Hamish and the team at NOW as they continue to execute their growth strategy, and see opportunities for NOW to work with Spark New Zealand to benefit customers."
The minority stake makes Spark the biggest single NOW shareholder. NOW was "overwhelmed" with interest from investors and its major competitor "seemed like the logical partner in terms of the strategic value they were going to bring", Mr White said.
"Looking at it from our customers' perspective we can see huge value."
Spark's stake was "a massive validation" of NOW's company culture and potential, "otherwise they would have invested in themselves."
It was business as usual - the two companies were still in "direct competition".
"They are no less a competitor than they were yesterday."
Mr White recently won the Linden Estate Leadership Award at the Westpac Hawke's Bay Chamber of Commerce Business Awards.
The former Telecom marketing manager was introduced to NOW by Havelock North businessman Rod Drury and joined its board.
Mr White structured a takeover and became CEO, directly challenging Telecom.
Mr Drury said the Spark stake was "nice work" by Mr White.