Now comes the tough part.

Dave McKay, the president and chief executive of Royal Bank of Canada, has spent much of his tenure as head of the second-largest Canadian bank by assets plotting the $5 billion acquisition of City National in Los Angeles.

Now that the deal has closed, McKay must execute on a cross-selling strategy focused almost exclusively on affluent customers of both banks. McKay sees plenty of low-hanging fruit in both banks' existing markets.

RBC owns a small Georgia bank providing basic banking services to Canadian "snowbirds" who winter in the U.S., but it needed a broader banking franchise that could offer more services to clients while keeping competitors at bay.

McKay, who became president and CEO of RBC in 2014, has worked for the bank nearly his entire career, including a stint as group head of personal and commercial banking. The first order of business will be to determine which clients to target first.

The nearly $900 billion-asset RBC will begin offering capital markets, investor, treasury and advisory services to City National's high-net-worth clients, many of whom operate middle-market businesses, a sweet spot for commercial banking.

Meanwhile, RBC's existing wealth management unit, with roughly 300,000 clients in the U.S., will be rolled into City National under a single line of business led by Russell Goldsmith, City National's longtime chief executive. Goldsmith, who was CEO of City National for 20 years, will still be based in Los Angeles and the unit will still operate under the City National name. RBC clients will be offered a broader array of mortgage, credit card and business-loan products.

Since 75% of RBC's bank operations are in Canada, the acquisition of the $36 billion-asset City National provided both geographic and economic diversity, McKay said. Unlike most mergers, no employees will lose their jobs and a few hundred will be added. City National brings 3,600 employees to the Canadian bank, including 2,100 financial advisers located mostly in California and New York.

Both men have been talking up the deal for so long that they could not avoid using classic road-show phrases like "optionality" and "lever our existing footprint" during an interview after the acquisition was completed this week.

McKay and Goldsmith talked about the regulatory process, the market for mergers and acquisitions, their cross-selling and other expansion plans and the pressure on banks to find new revenue sources.

What have you learned from the regulatory process surrounding M&A?

Dave McKay: I think it was an excellent process. It starts with communication and ends with communication. We spent a lot of time discussing our strategy with the [Federal Reserve] and the [Office of the Comptroller of the Currency]. We had a lot of discussion about what we wanted to do and how we wanted to go about it even before we got to a transaction. It was a big part of the foundation to the relationship, and when the transaction opportunity came up, they weren't surprised by it. It was a relatively smooth regulatory process with the Fed.

Russell Goldsmith: Part of the process RBC and City National went through validates the importance both companies have placed on trying to live up to the highest regulatory standards and having strong relationships with the regulators. Both companies came into the process from a credible place and worked cooperatively with key community groups, and we reached an extensive [$11 billion ] commitment with the community, and by taking that approach it made the process easier.

What do you think of the current mergers and acquisitions market?

DM: It will be a little more active going forward. The challenge in 2008 and2009 was that banks were repairing their balance sheets and they may not have been allowed to be active. Our transaction was the largest [by RBC] in the last decade. But valuations are pretty rich right now.

What's first on your agenda for City National?

DM: We put rocket boosters on City National. It's an exciting opportunity on a number of fronts. Our existing wealth management franchise is the eighth-largest, and many of our customers only have an advisory relationship with RBC. Now they will be introduced to wealth management, and it's a significant opportunity to grow and cross-sell our existing client base.

[City National's] commercial franchise is an opportunity to grow our capital markets franchise, and put our trillion-dollar balance sheet behind City National.

There's an opportunity to cross-sell each other's customers, and expand the existing franchise model, and look at new markets like Houston, Washington D.C. and London, to lever our existing footprint.

What kind of pressure is there to find revenue and loan growth with interest rates so low?

RG: Growth over the last few years has been very robust because we're in some very robust economies.

We do think over time that having the relationship with RBC's wealth management and capital markets will present a lot more opportunities. I hope we can sustain a reasonable level of loan growth organically and do better than that.

DM: The pressure [for growth] is acute on mass retail banks that tend to be deposit-centric, and they tend to have national credit card and auto lending franchises. The beauty of being a private and commercial bank is to grow deposits and assets, which is the key to driving shareholder returns.

What's your first item of business after the merger?

DM: We could have an organic entry or additional M&A in the future. We have so many organic opportunities — that's going to be the priority. In the first quarter of 2016, we're going to open a branch in Manhattan. We are leveraging our existing footprint. We just announced a new building in Bishop's Gate [in London], and in Houston where RBC has strong capital markets. Washington D.C. would be a new market for both banks.

The beauty of this transaction is it gives us long-term strategic optionality and over the long term we have strategic optionality to grow our customer franchise where it makes sense.

RG: This is a very positive growth story, unlike so many mergers. Nobody is getting laid off, we hired 100 new colleagues and we're planning to hire at least as many next year. We're going to continue to look at the very best talent

We are now part of a full-service financial services company. And RBC got an incredible bargain.

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