"There's more coverage in stocks that are in the 50 as opposed to outside the 50," he said.
"And you also have indexes that will only hold stocks that are in the top 50, so you have more buying interest in the stock as well."
Mr Craig said, in statement to the NZX, that inclusion was another positive step forward for Comvita on its journey to becoming a truly global, natural health products company.
"Recently, we affirmed our strategic plan to deliver $400 million of revenue by 2020, and index inclusion will increase our relevancy to New Zealand and offshore investors," he said.
"We welcome new shareholders who share our vision of realising Comvita's potential in delivering naturally sourced health products to the world. Index inclusion is also rewarding for our existing, very loyal shareholder base who have supported Comvita over many years. We look forward to further opportunities to grow value for them."
There were just four Bay of Plenty companies listed on the NZX - Comvita, Trustpower, Port of Tauranga and Seeka Kiwifruit Industries.
S&P/NZX 50 Indexs:
* Comprised of 50 of the largest and most traded companies listed in New Zealand.
* Covers approximately 90 per cent of the New Zealand equity market by capitalisation.
* S&P Dow Jones Indices and NZX agreed to co-brand the suite of NZX Indices in June 2015, when S&P Dow Jones Indices assumed responsibility for calculating, maintaining and licensing.