Our next presentation is Willis Towers Watson. Willis Towers Watson is a leading global advisory, brokering, and solutions company that helps clients around the world turn risk into a path for growth. Our presenter today is the CEO, John Haley. John is currently Chief Executive Officer and Director of Willis Towers Watson. He has served in these roles since January 4th, 2016. John joined the company in 1977, and throughout his career, served in a variety of roles, including consulting actuary to several of the company's largest clients, manager of the Washington, D.C., consulting office, and leader of the global retirement practice. John was named CEO in 1998. Under his leadership, the company went public in 2000 and completed three historic mergers in 2005, 2010, and 2016 that form present-day Willis Towers Watson. Please join me in welcoming John Haley. John?
Thank you. Thanks, Blake. Good morning, everybody. It's a great pleasure to be here at the Nasdaq conference. First, we have the usual forward-looking statements and non-GAAP measures slides here. Let me jump right in here. We had a merger back in January 1, 2016, which brought together Willis, the brokerage organization, largely in brokerage, number three broker in the world in terms of just general corporate risk, and also number three reinsurance broker in the world, and Towers Watson, which was the number one human resource advisory actuarial consulting firm. This brought together two firms which were the leaders in their respective businesses. What we were looking at is the confluence of risk, that risk and people are something that we think comes together increasingly.
We also think that the kinds of solutions that our clients are looking for are ones that increasingly involve, say, brokerage services. Those from the Towers Watson side were increasingly finding that we needed brokerage services to deliver on some of the solutions that we had. I think from the Willis side, they were looking for something that would complement what the brokerage services were. In particular, I think the fact that Towers Watson had healthcare exchange services in the U.S. was seen as a growing opportunity that Willis wanted to make sure they took advantage of. The team that we have among our leadership team is quite a seasoned team. The operating committee has the average service is around 20 years with the organization, and even longer, obviously, in the industry generally. We're people who know what we're doing.
We have a disciplined and a focused approach to management, and we have some history of having done successful M&A transactions. When we announced the merger, we talked about ways that we would create value, and I'll talk a little bit more about them in a few slides, but basically, we thought we could get some cost synergies. We thought we could get some tax savings, and then we also thought we could get some revenue synergies. We're well on our way towards achieving each of those three. We are focused on enhancing free cash flow. That's one of the big objectives we have going forward in the next few years here. Let me talk a little bit about the organization. Willis Towers Watson has about $8.25 billion in revenue. We have an adjusted EBITDA of a little over 23%. This is for 2017, so about $1.9 billion.
We're an organization of a little over 43,000 colleagues at the moment, and we're in about 140 countries around the world. The pie charts there show our distribution. We're organized into four global lines of business or segments, as we call them. The largest of those is our Human Capital and Benefits. The Human Capital and Benefits is an amalgam of some business that came from Willis and some business that came from Towers Watson. It's largely from Towers Watson, but Willis did a lot of work in providing retirement and healthcare solutions through their brokerage services. Almost $1 billion of this came from, and it's a little over $3 billion, but almost $1 billion of this came from the Willis side. The second-largest one is Corporate Risk and Broking, and this is something that came over 100% from Willis.
It's the business that, as I said, was the world's third-largest Corporate Risk and Broking business. It's a global business, and we'll talk about the geographic spread in a little bit. The third-largest business is, again, a mixture of businesses that came from Willis and from Towers Watson. It's called Investment, Risk and Reinsurance. The investment consulting arm came from Towers Watson. The investment consulting is done largely to pension plans. We work with them to set their investment philosophy. We work with them then to implement that philosophy. And increasingly, we're finding that business shifting from what used to be a consultative approach to more managing the business. Having set the investment philosophy, we function as the chief investment officer and actually hire and fire the managers on behalf of the client.
As I said, it's largely pension plans, although we do have some charities and endowments and some sovereign wealth funds, increasingly, that we do that work for. The Insurance Consulting and Technology, Towers Watson was the world's largest actuarial consultant to insurance companies. That business has been in the new company renamed as Insurance Consulting and Technology. It came over intact from Towers Watson. We continue to be the leader in this business, and it's a business that increasingly we're finding it shifting from consulting to technology. The software piece of the business has been growing rapidly. The consulting end of it has been stagnant or slightly declining. But what's happening in the software business is making up for that, and frankly, the software business is a more profitable part of the business for us. Then we have reinsurance.
One of the gems of Willis was the reinsurance brokerage business. As I said, third largest in the world and a very significant presence there. The smallest piece of the business, a little bit under 10%, is the healthcare exchanges. We run healthcare exchanges in the U.S. These are not the Obamacare exchanges. These are private healthcare exchanges. So when companies want to provide their, say, retirees, companies that have retiree medical want to provide their retirees with some choice. Among them, they'll go to our healthcare exchange. For the retirees, we have a little over 100 insurance companies on our exchange. We have at least five in every zip code in the U.S., so we're able to offer significant choice to them. And it's not just companies, I said companies, but actually it's also some big states.
For example, the Ohio state is one of our clients, Ohio Public Employees Retirement System, actually our largest client. We also do that for actives. We have fewer insurance companies that we would provide for an exchange. We try to keep that to a relatively few for the actives, but probably about four or so that we would be using on a given client. That's the smallest piece, but also the fastest-growing piece of our business. About 50% of our revenues come from the U.S., well, North America, so the U.S. and Canada. The second-largest operation is Great Britain. They're at about 22% or so. Interestingly enough, for both Willis and for Towers Watson, that percentage was almost identical for each of them.
Both had significant operations in the U.K., particularly for Willis, it's the heart of the company, where it started and where a lot of the intellectual capital resides. Western Europe, coming in a little about a billion and a quarter of USD revenue is about 16% of the company. Asia Pacific and Latin America is about 12%. I've talked a little bit about some of these business segments already and what we do. I guess the point I would make is that the Benefits Delivery and Administration, which is where we have the healthcare exchanges, we also administer healthcare plans for corporations, and this is almost exclusively a U.S. business that we have here. That's where the big healthcare administration is. That, as I said, is our smallest business, but also our fastest-growing. The Human Capital and Benefits business has our retirement business in it.
The retirement business is about a sixth of our overall USD revenues, something like that, about 16% or so. It's about 24% of our profits. Very profitable business, but very slow. The growth is probably 0%-2%. It's a relatively mature business, not particularly fast-growing, but we love the profitability, and we love the fact that it's sort of an island of stability, and it gives us the opportunity to invest in other things. We are a large healthcare consultant that's in the Human Capital and Benefits. That's a business that is largely the U.S. also, although we're seeing interest in healthcare, particularly interest in supplemental healthcare plans around the world. When I go to Asia, sometimes that'll be some of the biggest focus among clients is issues around supplemental healthcare plans. Talent and rewards, we're the world's largest exec comp consultant.
We also do employee opinion surveys. We will come in and measure employee engagement, what their feelings are about them. We usually try to repeat them every two to three years, so we have a sort of a moving picture of what's going on with employees and how they're feeling. We're able to test how different programs are working or not working for the organization and for the employees. We have the world's largest normative database of employee opinion survey results. When we get these results, we're able to deliver a rich understanding of what these mean. We're able to put them in a lot of context. Within Human Capital, we have our Global Services and Solutions. That's something that uses exchange-like principles to deliver healthcare around the world.
It's one of the things that we had identified in the merger as a revenue synergy, and it's probably been the most successful revenue synergy that we've seen. I talked a little bit about the Investment, Risk and Reinsurance. Let me mention a couple of characteristics of them. As I said, the investment consulting, we're seeing that move from consulting to more of our, increasingly, we are providing delegated services. That is to say, we function as the chief investment officer and hire and fire. It sort of mirrors what's happening in the investment business. I mentioned there, in the Insurance Consulting and Technology business, I mentioned there the software is the fastest-growing piece, and the consulting is somewhat slower growing or maybe flat. Same kind of thing in investment. It's the consulting piece that is somewhat flat, and it's the service piece that is growing again.
This is something that we're seeing across our different businesses, and we're pretty excited about, I think, the smaller but much faster-growing pieces of the business in both cases there. Our reinsurance business just continues to do extraordinarily well in what's been a reasonably tough market for reinsurance. The premiums have been declining. They've been declining, I guess, at a slower rate in the last two years, but still declining or flat. Our business continues to provide a lot of value to our clients and continues to perform very well from a financial standpoint. Corporate Risk and Broking, we are, as I said, the third-largest player. We have a different mix to that business in the U.S. than, say, we do in the U.K. In the U.S., we have a relatively small percentage of the large market.
We're probably in between 3% and 5% of the large market in the U.S. One of the goals of the merger was to get that percentage up higher. In the U.K., it's more like between 15% and 20%. We think we can do it. It's been a little bit slower going than we thought it would be, but we are making some significant progress against that result. Oops, sorry. I talked about the merger, some of the benefits we were looking to get out of that. One of the things we wanted to do was to take advantage of some of the relationships that Towers Watson had among large clients and use that to introduce some of the services that Willis had. You can see here, this servicing 82% of the Fortune 1000 and 78% of the Fortune Global 500.
Those are almost the identical numbers that came from Towers Watson, which has a very longtime presence in the large companies in the U.S. and around the world. Particularly where we felt we were underrepresented in the U.S. market, we wanted to use our relationships with these large companies to introduce brokerage services. That's the path we've been on. As I said, it's been a little bit slower going than we thought it would be, but we are making some significant progress. On the other side, Willis, particularly in the brokerage services, had a very large presence in the middle market. One of Towers Watson's strategies, really across the business, but consistent with the trends I mentioned in investment consulting or in Insurance Consulting and Technology, where it's the software part of the business, it's the technology part that's becoming more important.
We had been embarked on a path to say we want to be creating more and more solutions. We want that to be a bigger part of what we're doing. We want technology offerings to be a bigger part of what we're doing. One of the conclusions we had was if we wanted to do that, we needed a bigger presence in the middle market because there's large clients, there's fewer of them, you don't have the same opportunity in terms of selling that big software. We wanted to get to these large number of clients in the middle market. Willis had 20,000 middle market clients. We thought that was particularly important for the healthcare exchanges, and that's one of the synergies going from Willis to Towers Watson. I've referenced a few times these merger goals.
The cost and tax synergies we said when we exited 2018, we wanted to have some cost synergies of about-- we targeted $100 million-$125 million. Of course, should have known better because when you target $100 million-$125 million, investors quickly interpret that as $125 million. That became our goal. We've actually done better than we thought, and we've raised that goal now to $175 million exiting 2018. We'll certainly hit the original goal for sure. We think we'll hit the $175 million also. In the tax synergy, the Towers Watson tax rate, effective tax rate, had been in between 34%-37% over the last few years before we merged. We said we would get down to an adjusted tax rate of below 25% by the end of the second year. Actually, we got there faster.
We've achieved that, assuming that the U.S. Congress doesn't do anything in the next year or so, we think we can say we'll have achieved that. We're ahead on both the cost and the tax synergies. The revenue synergies are a little bit more of a mixed bag. The group health and benefits, that's this global healthcare solutions I talked about. As we said, we expect to meet the original target of $75 million. That's a bit of an understatement. We passed that, I think, in March. Yeah, we expect to meet that, is safe to say. We expect to be at the lower end of the $100 million-$250 million range in the mid-market exchange business. We had a bang-up first year in 2016, and in 2017, we saw much slower growth in that market.
We believe that we were by far the market leader in 2017. The problem was that with Congress talking about potentially redoing Obamacare and throwing it all out and everything, that puts a bit of a chilling effect on the market, particularly people moving. While we probably had the best 2017 of anybody, the market just wasn't very good at all. That's why we think 2018 is going to look more like 2016 than it does like 2017. That'll get us around the lower end of that $100 million-$250 million range. With property and casualty, we had set a target of $200 million for the large market sales in the U.S. We expect to exit 2018 with about $150 million.
I mean, we've had a little bit fewer sales than we had expected, although the number of sales is not that far below what we had. The dollar amount per sale is a good bit lower, and that's really the large part of why we're at $150 rather than $200. I think putting the best face on the $150, it is an improvement. By the way, to look at this, Willis had total revenue of about $350 million, something like that, from the large company P&C market when we entered it. We've added $150. It's not as much as we had hoped for, but it is a significant increase. We don't see this synergy as anything that all of a sudden ends at the end of 2018. We're going to continue to focus on that.
One synergy that we did not talk about was the reinsurance and the Insurance Consulting and Technology. That is one that we thought was there, but we didn't articulate it to investors at the beginning. That's delivered more than $25 million. The net of all of this is that while we're not ahead on every individual synergy, we are ahead on the combined revenue and cost synergies. A word about our financial management philosophy. We are a relatively disciplined company. We are relatively conservative in how we manage things. We're looking to make sure, and when you have a merger, there's a lot of different things going on, but one of the philosophies that we're establishing for the new company is to make sure we manage everything with acute attention to financial discipline. 2016 was a bit of a rocky year for us in that regard.
I think 2017, we did very well, and the first quarter of 2018 has continued that and then some. One of the things I referenced earlier, we're looking to drive free cash flow. Free cash flow is something that has not been that good for a number of years now. There's been various restructuring programs. We've had the cost of the merger and everything. For 2018 and beyond, it's probably going to be one of the top two focus areas for us. Capital allocation principles, we want to maintain a low investment-grade rating on our debt, then we want to return the excess cash to shareholders. We will look for good opportunities if we can find them for merger and acquisition. I think right now, we see one of the most attractive opportunities is actually buying back our shares, so we've been continuing to do that.
We like the idea of transparency and clarity around what our goals are and what our results are. We like sharing them with investors, when we've done well, celebrating that, when we've done poorly, just being clear about why we haven't done well and then what we're going to do to fix that. The last point is just we want to meet commitments and build trust. This slide shows the return on capital since the merger, $544 million in cash dividends to date. We have talked about a payout ratio of between 20% and 25%. I think we're closer to about 24% right now.
We had a 13% increase in the quarterly cash dividend this year as we went from $0.53 to $0.60. That was in line, I think, the $0.53 was about a 25%. We're now at 24 with $0.60. Share repurchases, we've done $1.1 billion of share repurchases, $1.1 billion of share repurchases to date. We're estimating that we'll do $600 million-$800 million for calendar year 2018. As I said, we want to maintain a low investment grade debt rating. That means a limit of 3.5 turns on debt to EBITDA. As I said, we also want to be opportunistic about M&A. We are also looking to clean up our businesses. We exited 10 smaller businesses in 2017. Actually one of them was in January of 2018.
We think we have that where we'd like it to be now. The focus is looking for the right M&A opportunities. We have about $250 million of CapEx and about $250 million of OpEx. The fiscal 2018 objectives, I think look, the big numbers are here, that we are looking to get to a 25% EBITDA margin. Our guidance is for $9.88-$10.12 in adjusted EPS and the free cash flow, $1.1 billion-$1.3 billion. I've emphasized free cash flow a lot. We think it's the area that we need the most focus on going forward, and that's why we're making it one of our top two objectives. Long term, beyond 2018, revenue growth, we need to make sure that we're growing as fast or faster than our competitors. That's not something that we achieved in 2016.
It is something we achieved in 2017 and in the first quarter of 2018. We need to make sure we have the right kind of operating efficiency. If we do that well, we think we can reach the double-digit EPS growth. The free cash flow, we'd be targeting 75%-80% of adjusted EBITDA. First quarter 2018, we're reporting on both the ASC 605 and ASC 606 basis. We've really focused on the ASC 605 basis because that provides us with the right comparison. There we had top line growth in the first quarter of 10%, 4% constant currency, 6% organic. The adjusted diluted earnings per share were $4.41 and an adjusted EBITDA margin of 33%. You can see that all of our businesses were up in organic revenue across the board in the first quarter.
The $4.41 earnings per share was an increase from $3.71 the prior year. The prior year was an exceptionally strong quarter. There were a lot of benefits from the second quarter of 2017 that flew into the first quarter of 2018, made it a very tough comparison. We still managed to do much better than we might have hoped. Let me just end on the key takeaways. One, we have a very strong and a very diverse set of clients. About 85% of our revenues are recurring. I talked about the strong management team. We see a lot of people are anxious to join us, the attracting and retaining top talent, we think we're in good shape on that. I talked about efficiency, ways we could get to double-digit earnings growth.
Again, you're going to hear us talking about free cash flow all the time. Do we have any questions on the app or-- Not on the app? Maybe I'll just see if there are any questions from the audience here.
About a month ago, one of your professional service company competitors announced that they were retiring some of their go-to-market brands. I'm talking about Aon Risk Solutions. Last year, they retired Aon Hewitt. Is that a course that you think you might follow over time? Is the Willis brand a strong enough brand to encompass both of them and all the four business areas?
I think we don't have any plans to change our branding. I will say that when we did the merger, one of the things we talked about was going to market in an integrated approach. We thought that was possible in a market where that hadn't happened. If you look at the kind of suite of services that we have or that our two biggest competitors, Aon and Marsh have, it is the brokerage, and it's also the human resource consulting, let me think. I remember a number of investors and analysts came back to us, and they said, "Geez, we've talked to your competitors, and they say they've been trying for decades to bring an integrated suite of services together, and it just doesn't work, can't be done here." We said, "Well, that may be.
It may be that we're wrong about that." We think that there's a need for that. Because we're relatively, instead of being a big brokerage company and a much smaller human resource, since we're two of equal size, maybe it's easier to bring an integrated suite of services together, and so we're going to try on it. I thought it was nice to see that our biggest competitors are now talking about integrated services and getting rid of their brands to follow our lead, and I think imitation is the sincerest form of flattery