Upwork confidentially filed for an initial public offering, Recode reported, citing people familiar with the matter. However, it could still pull back its plans or get acquired instead.

When contacted by SIA, an Upwork spokesperson said the company cannot comment on the news.

“There are surprisingly few public human cloud companies (Freelancer.com being the one notable exception), and this could easily become the largest and most notable transaction in the industry’s history,” SIA Research Manager David Francis said. “If Upwork goes through with an IPO, it sends a strong signal that the industry is maturing, and I suspect would be a welcome development to all stakeholders.”

Upwork ranks as the largest business-focused human cloud platform with $1.36 billion in 2017 gross spend, according to Staffing Industry Analysts’ “The Gig Economy and Human Cloud Landscape: 2018 Update” report. The company posted double-digit growth year over year in 2017, by SIA’s estimates, with the majority of growth attributable to gains in its enterprise business.

Two of the largest online staffing firms — oDesk and Elance — merged in 2013 and relaunched under the Upwork brand in May 2015.