Social media firm Snap Inc may be the highest profile tech IPO planned for 2017, with the potential to raise billions. But more than a dozen expected stock offerings of relatively obscure software firms targeting business customers - little-known names such as Apttus, Tintri and Okta - could be just as important in thawing a long-frozen IPO market, according to investment bankers and advisers who work on IPOs.

Such firms are a "leading indicator" of broader investor demand for market debuts, said Justin Smolkin, head of Americas technology equity capital markets at UBS Group AG.

"They tend to be viewed as cream of the crop, and where investors make the most money," he said.

Such enterprise software companies generally sell their services through subscriptions that produce reliable revenue streams. They aim to sign contracts lasting several years, giving investors more predictable returns than many Internet or consumer-oriented companies that depend on advertising or high volumes of individual transactions.

The firms provide a range of back-of-the-house services, such as automating business processes, security, accounting, training software and expense management.

Although such companies have moderate valuations, between about $500 million and $4 billion, the sector accounts for most of the tech IPO market, said Will Connolly, Goldman Sachs Group Inc's head of US technology equity capital markets.

"Most of the technology IPO activity is actually not big, large-cap companies going public," Connolly said. "It's small and midcap growth companies going public that are innovators in their own markets and are helping drive the next generation of technology."

Reuters has identified more than a dozen US enterprise software companies that are making preparations for a 2017 IPO including Avalara, MuleSoft, ForeScout Technologies Inc, AppDynamics and Yext. In 2016, only six software companies went public, Thomson Reuters data showed.

Greg Becker, chief executive of Silicon Valley Bank, a lender to venture capital-backed companies, predicted that between 30 to 45 venture capital-backed technology companies could go public in 2017, compared to 15 in 2016.

These companies could also be aiming to get ahead of tech giants Airbnb Inc and Uber Technologies Inc, whose long-anticipated IPOs would require ample investor dollars and attention.

If the enterprise software firms' IPOs succeed, it could offer a boost to early-stage investors who provided key funding in the hopes of profiting by selling shares down the line. Only 20 technology companies went public in 2016, less than any year since 2008, according to Thomson Reuters data.

"It will be important for everyone that these deals work well in the market to create positive momentum for the year," said Anthony Kontoleon, global head of syndicate in the equity capital markets group of Credit Suisse Group AG.