Dropbox CEO Drew Houston, left, and Box CEO Aaron Levie. Steve Jennings / Getty Images, Richard Drew/AP The market for business file-storage software has been one of the most competitive fields in tech over the past few years.

More than 100 vendors are competing in this space now, ranging from upstarts like Box and Dropbox to the big players like Google and Microsoft.

But this market, broadly known as "enterprise file synchronization and sharing," is ripe for change and could end up losing 70% of the companies over the next two years, according to market research firm Gartner.

"By 2018, 70% of EFSS destination vendors will cease to exist, having been acquired or put out of business, and the remaining 30% will evolve to support the digital workplace or modernize corporate data infrastructures," Gartner wrote in its latest "Magic Quadrant" report for the EFSS industry.

The report notes that there's "fierce competition" going on in this space, causing the simple file-storage functionality to become commoditized and offered at almost no cost. That would cause smaller players with no differentiating features or bigger companies that see little reason to expand to entirely back out of the industry.

In the meantime, the remaining leading vendors will either focus on building up their work collaboration features or become full-scale backend repositories for data and files, the report predicts.

Gartner picked four companies to lead this space, including Box and Dropbox, the two most popular names in EFSS, and Citrix, a $13 billion publicly traded company with a variety of products used by companies with mobile workforces.

The big surprise winner here is Egnyte, the nine-year old startup that has raised $62 million — a fraction of what some of its competitors have.

Gartner

The top four vendors offer similar storage services but differ primarily in whether they're cloud-only or offer a mix of cloud and on-premise storage. Box and Dropbox are only available over the web, while Egnyte and Citrix let users take a "hybrid" approach, allowing them to store files both on the web ("cloud") and in their own data centers ("on-premise").

This infographic from Skysync should give you a better idea of how it works: