The deal—announced in December 2024—will create the world’s largest advertising and marketing company and mark a major shift in the industry as AI and technology reshape the way agencies work with clients.

Wren, who has led Omnicom since 1997, sat down with Fortune at Web Summit Qatar to discuss why this deal is happening now, how it will impact clients and employees, and what lessons he’s learned from past merger attempts. He also explains why, after nearly three decades at the helm, he’s still focused on shaping Omnicom’s future.

The following has been condensed and lightly edited for clarity.

You’re going through what’s been described as the “merger of the century” between Omnicom, your company, and IPG. Your company sits 287th on the Fortune 500. Why is this something Omnicom needs to do? Why is it important?

I thought we were 187th, but we’ll move up after this. This is a once-in-a-lifetime opportunity. Up until now, there was no real reason or impetus for us to come together.

However, over the past couple of years, it has become more obvious that to stay at the cutting edge of the necessary tools and services we provide to our employees—and in turn, our clients—it made more sense to bring our two companies together.

Both Omnicom and IPG are American-based, which makes the mechanical aspects of the merger easier. Culturally, our companies have shared employees over the years, so our work environments and values are familiar to both sides. But more importantly, the use of data and AI has transformed our industry. IPG has made certain acquisitions, and we’ve made very serious investments in an operating system called Omni.

IPG has fantastic assets; one of their standout assets is Axiom, the gold standard of data. When we integrate that into our Omni network and Flywheel, which deals with retail and consumer activity, we’ll have the best view of consumers available. This will allow us to create unique IDs for individuals around the world, enabling us to target and influence consumers while respecting their privacy. So yes, this merger is a huge opportunity—once in a lifetime.

Web Summit

Do you see this as future-proofing Omnicom for the long term?

It’s about as close as you can get to future-proofing. The idea behind the transaction is to enhance the quality of our tools, the quality of our data, and the free cash flow both companies generate. This will allow us to increase our investments in both rapidly evolving technologies and other areas that benefit our clients.

You went through an attempted merger in 2014 when Omnicom tried to merge with Publicis. What’s the single biggest lesson you learned from that past attempt that you’re determined not to repeat this time around?

Probably clarity. The merger 10 years ago failed because there wasn’t enough clarity. That deal was framed as a “merger of equals,” and there wasn’t a single point of decision-making. Employees didn’t have the comfort of knowing who was in charge or who was looking out for their careers. That’s the biggest lesson.

There weren’t as many scars as there were lessons—quite an education, really. That merger took nine months before it fell apart. This time, Omnicom is acquiring IPG, though we are treating them with the same respect as if it were a merger of equals. They have incredibly talented people and deep client relationships with some of the biggest marketers in the world. Philippe [Krakowsky], IPG’s CEO, is joining our board of directors, which reflects the level of respect we have for them. But there will be clarity in direction and leadership this time.

Web Summit

Let’s talk about clients and culture. What can clients get from this new Omnicom-IPG combination that they couldn’t get before?

Without the merger, both Omnicom and IPG would have to make similar investments in AI separately, building parallel platforms. But together, we can focus on a single platform and a unified set of tools, democratizing them for our 120,000 employees worldwide. Clients will benefit from that.

Another benefit is that many clients have been working with both companies, purchasing services and data tools separately. No client has ever asked us to collaborate in the same room to find a better solution. Now that we’re merging, we can uncover inefficiencies and create untapped value for clients.

How do you see generative AI reshaping creative work?

AI is already changing the way we work. We have about 6,500 employees embedded in AI-driven workflows, testing models and improving how we generate campaigns.

For example, if you wanted a campaign scene set in Tokyo during a rainstorm, an artist used to have to create detailed storyboards, which took time. Now, AI can generate that scene in seconds. If the creative team doesn’t like it, they can iterate quickly.

Culture is often where mergers fall apart. How are you planning to blend the cultures of both companies? For example, I imagine not every business has the same return-to-office policy.

At the core of our business is talent. Our assets go in and out of buildings or work from home every day. Clients hire us for our talent, so we need to ensure our people thrive.

Both companies have similar cultures, but the real culture employees care about is tied to the brand they work for. We will respect those brands and listen to their clients to determine what should remain unchanged.

As for return-to-office policies, there’ll probably be a couple of disruptions depending on where you are, who you are, and in what market, but for the most part, we’ve been flexible. We require employees to come in three days a week in the U.S., but different markets have different policies. We found that’s a sensible balance. We saw during COVID that people got used to taking their kids to school, or going to their events or doing various things.

We looked at where employees live, and then we started leasing spaces that they could come to that it was within a 20-minute drive of their home. That gave them the flexibility. So we’ll increasingly do things like that, and some attempts will fail. At one point, I had a brilliant idea of starting an Omnicom bus company to bring everybody in. I could have sent a helicopter for the few people that used it.

Mergers and acquisitions can be a disruptive time for employees. How are you ensuring top talent stays?

Right now, we’re in a regulatory approval phase, which means we can’t be as specific as we’d like about future plans. We both have to individually run our companies as if the merger was not going to happen, and so it does leave employees a little unsettled, especially when you throw the word “acquire” into the equation. But it’s going to be a meritocracy with the best talented is going to emerge in leadership positions.

There’s a full-blown communication plan we’re going to be getting out and saying as much as the lawyers and regulators will allow us to say to give people that assurance. I think I’ve said since the announcement of the merger that if you are in a revenue-generating position working with a client the day before the merger, your job is actually safer with the merger than it might have been before because we have more tools to keep that client relationship. I can’t send that message out enough. There’ll be plenty of seats, plenty of career opportunities for all the important people in both organizations, and we hope to keep as much of our talent as possible.

You’ve previously mentioned that you could have easily coasted into retirement. Why did you choose to do this merger? What’s driving you?

I’ve been extremely fortunate. I’ve been the CEO of Omnicom for 30 years, and at a public company, that’s unheard of. It’s made me successful, it’s made me wealthy, and I take none of that for granted.

I owe Omnicom most of the success that I’ve experienced, and with that comes an obligation to build it and leave it with the best assets, tools, and employees that I can possibly do. And that’s why this IPG merger is so attractive to me.

If you are only concerned with this year or next year, Omnicom was doing just fine without the disruption of a merger. It would have been very happy, and some of the investors and others are a little bit confused as to why we actually took the action to do the merger, but I want to leave every employee in the new Omnicom with the most state-of-the-art tools that are humanly possible to aid them in servicing their clients. And I want to distinguish us in a way that we’ve not been able to distinguish ourselves before, in that having the depth of assets that we will have will be something no one will be able to replicate.