The NYSE, which is owned by Intercontinental Exchange Inc, said trading firms with 100% of their floor staff vaccinated can increase headcount at their booths, and while vaccinated traders still have to socially distance, they can remove their masks when seated.

"Given the fact that so many more people are vaccinated now, we can start to ease off on some of the restrictions that we've had in place since we reopened," Cunningham told CNBC.

The NYSE floor is the last physical U.S. stock trading venue, as a slew of all-electronic competitors have emerged and eaten away at the Big Board's once dominant market share.

Futures exchange operator CME Group Inc said on Tuesday it would permanently shutter the physical trading pits it closed last March due to the COVID-19 pandemic.

The 144-year-old London Metal Exchange said last month it will announce around June 8 whether it will reopen its open outcry trading ring or permanently shut the only such floor in Europe.

The NYSE closed its trading floor in March 2020 and moved to electronic trading for the first time in 228 years after several traders contracted the coronavirus.

The exchange reopened the floor, which it also uses for its opening and closing bell ceremonies, to tout initial public offerings, and as a backdrop for several television news programs, in May 2020 with reduced capacity and extra safety measures.

Cunningham said the NYSE floor is currently at around 50% of its pre-COVID capacity.

(Reporting by John McCrank; Editing by Alexander Smith)

By John McCrank