The protocol, according to the Deputy First Minister, is to thank for Almac's announcement that it will hire 1,000 people because it has dual market access.
In the next three years, the Almac Group, a Craigavon-based pharmaceutical development and production company, plans to hire 1,800 people worldwide, 1,000 of whom will be in Northern Ireland.
The development, according to Ms O'Neill, demonstrates the benefits of the protocol's dual access, which allows Northern Ireland firms to sell without limits in both the UK internal market and the EU single market.
Almac, which was participating in clinical studies for Covid-19 vaccines last year, promotes the protocol's "seamless, uninterrupted, and flexible" dual market access on its website.
Ms. O'Neill stated that the announcement had given the local economy a much-needed boost.
“The Almac announcement today is a very positive announcement in what is quite a challenging time for our economy because of the pandemic and because of the outworking of Brexit,” she said.
