A trader works on the floor during the Slack Technologies Inc. IPO at the New York Stock Exchange (NYSE) in New York, June 20, 2019.

Slack Technologies' reference price was set at $26 per share, the New York Stock Exchange announced Wednesday evening.

That does not necessarily mean Slack's Class A shares will open at $26 when they make their stock market debut on Thursday.

A reference price is not an offering price. It is also not an opening price. That number will ultimately be determined by the designated market maker, based off a calculation of a figure where buy orders can be met with sell orders.