Steven Sonnenstein on DigitalBridge’s Tower-Led Vision

Driven by a comprehensive, technology-forward approach that leverages scale, expertise and innovative thinking across multiple asset classes, DigitalBridge has ownership and managerial oversight of more than 600,000 telecom antenna sites worldwide.

The global alternative digital infrastructure asset manager has also ventured into emerging sectors like outdoor media infrastructure, uniquely positioning it to navigate the rapid evolution of connectivity and data needs.

As its Senior Managing Director at DigitalBridge Investment Management, Steven Sonnenstein not only leads the firm’s global tower practice and specific adjacent infrastructure initiatives but is also a key driver of the firm's forward-looking and integrated strategy.

“We own and operate 11 tower companies globally which gives us a clear view of the market – we see what’s coming, how it’s evolving and the dynamics across valuation, operations and financing,” he says. “It means we can anticipate rather than react.”

For Steven, that perspective proves why diversification matters – across geographies and verticals. DigitalBridge’s edge is that its leaders aren’t just investors, they’ve spent decades running and building infrastructure globally, bringing real operating know-how to every asset.

Pairing industry knowledge and capital

DigitalBridge’s origins as both operator and investor uniquely position the company to take advantage of shifts in technology and market behaviour. Its combination of scale and operational insight has enabled the firm to play a leading role in digital infrastructure’s transition to the cloud, next-generation telecom and the rise of AI.

Steven says: “We’re the largest private owner of towers in the world, according to TowerXchange. Our networks handle tremendous amounts of data traffic – and none of this works without towers. Right now, investors are focused on data centres, but cloud and AI compute ultimately have to connect back to smartphones. To make that work, networks need to densify exponentially from where they are today.” 

For Steven, AI marks a once-in-a-generation inflection point – bigger than the leap from 4G to 5G. Delivering on its promise, AI will demand unprecedented levels of investment in towers, rooftops, and edge infra to enable near-instant communication.

But the surge in demand brings a stark challenge. “The biggest issue we face globally is power,” Steven cautions. “The availability of energy to supply AI and data centre compute, on top of growing communication networks, is going to be the defining constraint.”

Towers: Connectivity’s unsung heroes

With a booming portfolio and stakes in several sector leaders, Steven emphasises that towers are not often the most visible element of the digital infrastructure narrative but play a foundational role. For him, the true value of towers is as the “starting point” in a broader ecosystem that connects to fibre assets and then data centres – where data is ultimately stored and processed.

The importance of towers is only growing with the rise of AI. While Large Language Model (LLM) training takes place in hyperscale data centres, AI inference – the real-time processing that makes applications usable on our devices – depends on the entire chain of connectivity. Towers and fibre are the critical links that move data to and from the cloud, ensuring AI workloads can reach users at the edge with near-instant speed.

It’s this vision that drove DigitalBridge’s 2021 acquisition of a controlling stake in Vertical Bridge, the largest private owner and operator of wireless communications infrastructure in the United States. Vertical Bridge today manages more than 500,000 sites, including more than 16,000 active towers. “Our role is to support the Vertical Bridge team as they build on their market leadership and capitalise on exciting growth opportunities,” Steven says.

One standout example is Vertical Bridge’s US$3.3bn agreement with Verizon, under which Vertical Bridge acquired exclusive rights to lease, operate and manage more than 6,300 wireless towers across the US. Under the deal, Verizon continues to use space on those towers via a leaseback programme. Vertical Bridge makes additional revenue by leasing tower capacity to other operators – converting what were once single-tenant sites into multi-tenant revenue drivers. “Verizon can’t deliver its service without the towers we own,” Steven says. “It’s a truly symbiotic relationship.”

In Europe, a similar model is deployed with Deutsche Telekom, where DigitalBridge co-invests in and operates tower networks alongside the operator and other investors – delivering growth, scale and shared upside.

Beyond cell towers

DigitalBridge’s portfolio extends beyond towers. The firm actively manages and operates businesses across the full digital infrastructure spectrum, including data centre platforms and fibre networks. By applying the same operating discipline to adjacent assets, Steven has helped expand the definition of what is considered digital infrastructure and launched outdoor media infrastructure. This new adjacency emerged from observing the similarities between telecom towers and billboards – both passive physical structures, generating recurring lease income.

“I spent a lot of time looking at the billboard space, because billboards are very much like a telecom tower,” he explains. “So, we created a company back in 2019 that focused specifically on acquiring the land and the physical structure of billboards in the UK.”

The result? In a matter of only a few years, a company built up to £50m (US$67.8m) of billboard cashflow before DigitalBridge exited, delivering strong returns to its investors. 

“Ultimately, it was a great success story,” he adds. 

Meeting the exponential rise in data centres

If towers are the starting point of connectivity, data centres are where its power is realised. For Steven, the sector represents both the greatest opportunity and the greatest challenge facing digital infrastructure today.

The numbers are staggering. The shift from on-premise servers to cloud platforms – and the explosion of AI workloads – will require capital expenditures in the trillions of dollars in the coming years. “The last estimates for investment requirements in the data centre space are in trillions,” Steven says. “We won’t even scratch the surface of the amount of opportunity that we can go and invest in.”

But with opportunity comes complexity. AI and cloud services demand facilities that can deliver more capacity, lower latency and greater resiliency than ever before. Meeting that demand means building new capacity at scale – from hyperscale data centres to edge facilities – to bring compute closer to end users.

The defining constraint, Steven warns, is no longer capital but power. “There’s not enough money or power in the world today to support the demand,” he says. Access to reliable energy has become the critical factor shaping where and how new data centres are built.

For Steven, this is where conviction meets vision: conviction in the discipline to select the right investments with rigorous due diligence, and vision to build sustainable platforms that can support the exponential rise of AI and cloud computing.

Looking ahead

For Steven, the future of digital infrastructure is shaped by two powerful forces: the global migration from 4G to 5G and the exponential rise of AI. Both will demand unprecedented levels of investment – running into the trillions of dollars – and both will create opportunities on a scale the industry has never seen.

But capital alone is not enough. “Our success is tied to making the right investments at the right time, but that does not exist without the right partnerships,” Steven says. For him, that means working hand in hand with management teams, customers and suppliers – the people on the front lines of running and scaling infrastructure every day.

The challenge ahead is to align all these stakeholders so that everyone is “rowing in the right direction”. By combining scale, timing and deep operating partnerships, DigitalBridge aims not just to capture opportunity, but to define the next era of digital connectivity.

For Steven, this is conviction and vision in action: conviction in the discipline to invest wisely, and vision to build the infrastructure that will power AI, 5G and beyond.