"They would have kept following him. It's like having Richie McCaw in the pack."
But Employers and Manufacturers Association chief executive Kim Campbell had an optimistic perspective on the Prime Minister's exit.
"People get spooked by change, but he was going to resign sooner or later, and he's chosen a good time to go with the economy in good shape.
"The business community will be upset because they liked him, but English is a very good choice to take over for now," Campbell said.
"He had a good innings. We wish him the best. He will be missed.
"But New Zealand will live to fight another day."
ASB chief economist Nick Tuffley predicted little impact in the short term, but heading into the next election the situation became less clear.
Another National victory would see more of the same as the party's senior MPs had not shown signs of going in radically different directions on economic or political issues, Tuffley said.
"Business as usual would be the best outcome.
The economy is in good shape and we're finally seeing the light at the end of the tunnel for dairy, our biggest export." Tuffley said English, the man behind much of the economic policy of John Key's government, would provide a steady interim leader.
Kirk Hope, chief executive of Business NZ, agreed that more of the same was the ideal outcome:
"From a business perspective we want the continued strong growth we've seen recently. The best outcome is that political continuity and stability continues," Hope said.
The worst-case scenario would be a repeat of Australia, with five Prime Ministers during Key's tenure. Key's timing wasn't ideal, with increased uncertainty in global politics underpinned by President-elect Donald Trump, Brexit, and the Italy referendum, but National had several strong senior MPs.
Westpac's acting chief economist, Michael Gordon, said Key's exit added a layer of uncertainty before next year's election.
"The economic policies of both of New Zealand's main political parties are relatively centrist. However, there are areas where their policies differ, such as housing," Gordon said.
"[Key] has pursued a conservative approach to managing the government coffers, focused on improving the fiscal debt position. Despite the coming change in leadership, we do not expect any major changes in policy ahead of next year's election."
ExportNZ chief executive Catherine Beard said Key "will be sorely missed".
"[He] has done a fantastic job on the trade front and put in a huge amount of work overseas. It's relentless stuff from very early in the morning to very late at night, and Key's opened a lot of doors to New Zealand businesses due to his hard work."
But he had been a team player and National should provide stable continuity to the economy, she said.
