ANN ARBOR – On Thursday, Duo Security announced it had raised an additional $70 million in a Series D round that propelled the software-as-a-service company’s valuation to more than $1 billion – only the second Michigan Venture Backed-technology company to pass this financial milestone.

Duo helps defend organizations against breaches with its two-factor authentication (2FA) app. Duo’s “Trusted Access” product suite verifies the identity of users and the health of their devices before granting them access to data and applications – helping prevent breaches and account takeover.

Duo also announced it has exceeded 10,000 customers and protects more than 300 million logins worldwide every month. Alongside this largest round of funding to date, Microsoft recently announced integration of Duo’s 2FA product into their Azure Active Directory (Azure AD) platform.

“Cybersecurity has become the biggest geopolitical problem of our time,” said Duo CEO Dug Song. “We are at a point where every organization in every industry is challenged with the overwhelming cost and complexity of securing a modern workforce. With this investment, we will continue to innovate solutions to the world’s most fundamental security problems, expand our global reach, and accelerate our leadership position in the industry.”

The Series D round was led by Meritech Capital Partners and Lead Edge Capital. It also included new investors, Geodesic Capital and Index Ventures, as well as existing investors Redpoint Ventures and True Ventures. A new strategic partner, Workday, also participated in the round. Duo now ranks among the world’s most valuable private SaaS companies with total funding of $119 million, and a company post-money valuation of $1.17 billion, the company said in a press release.

Duo also said it has added Lorrie Norrington, Operating Partner for Lead Edge Capital, former eBay President and former Board Member for McAfee, to its Board of Directors and Rob Ward, Co-founder of Meritech, as Board observer.

“In a world with innumerable security products that are difficult to implement, use and maintain, Duo stands alone as a vendor beloved by its customers and end users,” said Rob Ward, Managing Director at Meritech Capital Partners. “As a result, Duo has established itself as the leader in cloud-based trusted access and we are delighted to support their rapid growth.”

Emily Henitz, Associate Director, Michigan Venture Capital Association

A billion-dollar valuation also is a major milestone for a Michigan technology company, said Emily Heintz, Associate Director of the Michigan Venture Capital Association.

When considering Venture-backed companies in Michigan, companies raising VC money and not yet gone public, Duo is the only one to be valued at a billion dollars,” she said. “Typically Life Sciences companies get this type of valuation in Michigan. Being able to see a tech company raise this kind of money shines a bright light on Ann Arbor and Michigan.”

Heintz said word on the street is Duo is positioning itself for an Initial Public Offering, often called an IPO. Means the company could in the near future be traded on Wall Street. That would bring huge amounts of money not only to Duo and its founders, but also a huge Rate of Return for its Investors.

The last tech company to be valued at $1 billion in Michigan was Esperion Therapeutics, when it was sold in 2004 to Pfizer for $1.3 billion. Esperion developed the statin drug known as Lipitor used to battle cardiovascular disease. After the sale, many of the founding executives went on to create new startups, become angel investors, and major players in the Michigan technology sector. If Duo goes public, Heintz expects the same thing to happen with its newly minted millionaires.

“It would be a sign of the maturing of Ann Arbor,” Heinz said.

Duo did not provide a spokesperson before this story was published.

But In the press release, Duo said it has more than doubled its annual recurring revenue for the past four years. But Duo consistently declines to provide financial guidance.

Some of Duo major clients include Dresser-Rand, Facebook, K-Swiss, Random House, Etsy, Yelp, Zillow, and Paramount Pictures.

Duo’s headquarters is in Ann Arbor, where it is expanding into a second building, and also maintains offices in Austin, Texas; San Mateo, California; and London.

Visit duo.com to find out more.