French IoT player Sigfox has defied naysayers and raised as much as €150 million (US$159 million) in a new round of funding that attracted Salesforce.com and energy giant Total as new investors.

The company has developed a proprietary wireless technology that can be used to connect objects such as smart meters and asset-tracking devices, which transmit very small amounts of data over long distances.

It plans to use the new funding to accelerate network deployment to 60 countries by 2018, from 26 currently, and reach a financial break-even point.

The funding comes despite recent criticism of the company's business model and technology. Detractors, including but not limited to a number of rivals, have attacked Sigfox on many fronts, arguing that its technology is unsuited to many Internet of Things (IoT) applications and that it will ultimately lose out to alternatives. (See Sigfox Said to Face Customer Backlash.)

Relying on the use of unlicensed spectrum, Sigfox's technology has emerged as one of several options for companies requiring so-called low-power, wide-area (LPWA) connectivity. Its chief non-cellular rival is the LoRa technology backed by Californian chipmaker Semtech Corp. (Nasdaq: SMTC), but it also faces competition from newer cellular standards including NB-IoT and LTE-M, which use licensed spectrum and can take advantage of existing LTE network assets.

Others have criticized Sigfox for demanding such a hefty share of revenues from its network partners. While the company functions as an operator in its own right, it has also teamed up with service providers in several markets. In 2014, Sigfox was reported by Light Reading to be demanding as much as 40% of service revenues from its partners.

Despite the doubts, Sigfox appears to have grown its business from just 7 million connections in June to more than 10 million today, although it has previously acknowledged that not all of the connections it reports are active.

Revenues reportedly came in at about $13.5 million last year, but Sigfox is said to be targeting domestic sales alone of about $100 million by 2020.

Reaching that figure will not be easy, however. Sigfox charges as little as $1 per connection annually, claiming these low rates give it a major advantage over LPWA competitors. But the rock-bottom prices also mean that Sigfox will need to add many millions of connections over the next few years to grow sales significantly.

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Nevertheless, Total said it was "motivated" to invest in the company after observing Sigfox's "capacity to accelerate the deployment of large-scale IoT solutions."

Cloud-computing player Salesforce.com Inc. , meanwhile, appears to see a big data opportunity in a tie-up with Sigfox. The French company has indicated that it will integrate its service with Salesforce.com's IoT cloud to generate insights about possible improvements to industrial processes.

Other new investors participating in the $150 million round include Alto Invest, Henri Seydoux, Swen CP and Tamer Group.

Sigfox also pointed out that a number of existing shareholders are re-investing in the company, including Bpifrance, Elliott, Intel Capital, Air Liquide, Idinvest Partners and IXO.

Bpifrance is a French investment bank and a joint venture between the Caisse des dépôts et consignations and EPIC Bpifrance, two government agencies.

That has prompted suggestions that Sigfox has relied heavily on French government funding in the past, although a Sigfox spokesperson previously insisted that Bpifrance "was far from being the majority [investor]" when discussing Sigfox's last funding round, which raised $115 million in February 2015.

Interestingly, two previous investors not included on today's list are Spanish operator Telefónica and South Korea's SK Telecom (Nasdaq: SKM).

Most cellular operators appear to have leaned toward either LoRa or 3GPP-backed standards, such as NB-IoT, for their IoT deployments.

Indeed, SK Telecom has described LTE-M and LoRa as its "two main IoT pillars," while France's Orange (NYSE: FTE) is similarly making investments in both those technologies. (See SK Telecom Sees LTE-M, LoRa as Its 'Two Main IoT Pillars'.)

Meanwhile, UK-based Vodafone Group plc (NYSE: VOD), a major supporter of NB-IoT, has been outspoken in its criticisms of both Sigfox and LoRa, telling Light Reading earlier this year that the cellular standard would ultimately "crush" those technologies.

— Iain Morris, , News Editor, Light Reading