Barclays Wealth, a unit of UK-based Barclays plc, has been making serious moves to expand in the market here in the United States. But there are lingering questions in some corners over whether it can really make a go of it here.

Barclays only has about 250 financial advisors in the U.S., but it is continuing a hiring spree that began last year. It hired 50 new advisors last year in the U.S. and plans to add another 50 to 100 this year. Those additions will be offset by some attrition, but one source familiar with the company said he believes the company is gearing up to be a big player in the U.S. wealth market, as opposed to selling off the unit. The pertinent question, he says, is whether it will continue to add advisors one or two at a time, or make an acquisition.

Barclays bought Lehman's private investment management business in 2008 when the U.S. company filed bankruptcy and has been using that as its base of U.S. operations ever since.

Lehman was known not to use recruiters when adding advisors, and although Barclays has used them sparingly, it is still hard for advisors to get in the door, says one recruiter familiar with Barclays and the former Lehman. Barclays is being very selective about new hires as it is ultimately going after only those who service ultra high-net-worth clients.

The company says it is in the process of investing more than $1 billion internationally to transform itself to a top-tier wealth manager catering to an ultra-high-net-worth niche.

Globally, the firm's 1,680 advisors oversee approximately 150 billion pounds or US $218 billion in assets under management. That's up from 100 billion pounds (US $146 billion) over the past four years. Chip Roame, managing principal of Tiburon Strategic Advisors, says Barclays also wants to grow its U.S. investment banking presence and wealth management is a natural offshoot.

In the U.S. wealth market, Barclays has added top managers as well as advisors. In June, it named Steve Houston as the head of Wealth Management Americas. Houston will be responsible for building the firm's high-net-worth client business and expanding its advisor network.

Houston joined Barclays in 2009 as global head of relationship management and distribution. For the 10 years prior to that, he worked in global wealth management at Bank of America Merrill Lynch in several senior roles including sales and product development leadership positions.

Barclays Wealth also hired Aaron Gurwitz last month as chief investment officer and head of research, economics and strategy. He will oversee the forecasting and research for clients. Both Houston and Gurwitz will report to Mitch Cox, Head of Barclays Wealth Americas and Head of Global Research and Investments for all of Barclays Wealth.

Despite those additions and other recent hires, Barclays is still a far cry from the wirehouses in terms of headcount. The big four wirehouses range anywhere from 7,000 to 18,000 advisors. Even some the regionals have upward of 2,000 advisors.

But that's not the market Barclays is aiming for. Given its strategy of catering to clients with $10 million or more in investable assets, it is looking to grow within the boutique space, competing head-to-head with the likes of Goldman Sachs, Deutsche Bank or Credit Suisse. Those firms all cater to a high-end clientele, and trade partly on the fact that they are connected to an investment bank. JPMorgan Chase is also climbing the ranks in the boutique niche.

One difference is that those other European companies are looking more to the Asian markets for growth opportunities. Even though the U.S. is the biggest wealth market in the world, it is extremely competitive and is showing little sign of growth, says Cath Tillotson, managing partner of Scorpio Partnership, a wealth management consulting firm based in the United Kingdom. "Where would you put your money, in the fast growth markets or the U.S. [if you were a company looking to expand]," she says.

Another question is whether a European wealth management firm can really bring its attitudes and strategies to the very different U.S. market.

Despite various attempts from European companies to export their brand of wealth management to the U.S., Tillotson says that the different cultures are still a major stumbling block. Those differences, as clichéd as it may sound, stem from the fact that most of the U.S. market has more of a brokerage mindset with less emphasis on holistic wealth management, she says.

That's partially a result of the nature of the markets they serve. A company that serves investors with less than $10 million in assets will usually do so with fairly standardizes services, Tillotson says. To truly provide one-on-one tailored wealth services requires an ultra-rich clientele.