VF Corporation, the owner of The North Face, Vans and Timberland brands, bought the business in November last year for an undisclosed sum.
The terms of the deal were not disclosed at the time but the financials were today revealed in the OIO decision.
In the decision, the office said it was satisfied the new owners had the "relevant experience and acumen and are of good character", and that VF Corporation had showed financial commitment to the investment.
Steve Rendle, chief executive and chair of the North Carolina-based retail giant last year said adding Icebreaker to its portfolio was a "special opportunity".
"Together, the SmartWool and Icebreaker brands create an advantaged position for VF as a leader in the growing and underpenetrated natural fiber category," Rendle said.
"Its natural fibre focus is an ideal complement to our SmartWool brand, which also features merino in its clothing and accessories," he said.
Icebreaker founder Jeremy Moon, who started the business in 1995 aged 24, said the deal was "a once in a lifetime opportunity" for both the company and New Zealand wool suppliers.
Chairman Rob Fyfe said Icebreaker was a "very small brand" in the global outdoor clothing industry.
"The opportunity to join VF's stable of globally recognised brands and to be able to benefit from their expertise, consumer insights, distribution and operating scale presented Jeremy and Icebreaker's board with the best opportunity to realise our ambition to become a $1 billion brand."
Icebreaker apparel is sold in 47 countries worldwide and last year made more than $220m in global sales. The company buys 25 per cent of the merino wool New Zealand grows and produces more than four million garments a year.
The company was said to have considered more than 24 serious offers to buy it before committing to a deal with VF Corporation.
