(Story updated to note that S&P recently lowered its rating on Weight Watchers to "sell" from "buy" on valuation concerns.)



) -- If you're still in a defensive investing posture after last year's stomach-churning market, it's time to consider buying the stocks of companies with impregnable market-leading positions.

Ratings firm Morningstar refers to them as "wide moat" companies.

A "wide moat," essentially, means a company has a distinct and sustainable competitive advantage over its peers that could protect its business in the event of a recession or a even a shift in the direction of its industry.

The width of a company's moat is a result of a number of variables, including its size, brand-name strength, unique technologies, and the difficulty its customers may have in switching to a competitor's products.

Those types of characteristics help keep a company and its cash flow stable in a difficult economy.

And Morningstar says that "companies that have generated returns on capital higher than their cost of capital for many years running usually have a moat, especially if their returns on capital have been rising or are fairly stable."

Morningstar found seven wide-moat companies with share-price returns ranging from 10% to 36% this year, a period in which the

S&P 500 Index

jumped 7%.

But indicative of how quickly things can change and the moat can start to evaporate, two big money managers that are on the list below, which was issued Feb. 6 by Morningstar, have seen their shares tumble within the last week on poor results from late 2011 because of investor withdrawals due to the markets' volatility as well as proposed regulatory changes.

Those firms,


(AB) - Get Report


Federated Investors

(FII) - Get Report

, face a new threat to their money market fund businesses, in the form of new regulations now being discussed by the Securities and Exchange Commission.

If enacted, they could result in the fund firms having to raise capital to provide greater support to their funds in the event of a panic, or another that would allow the net asset value of money market fund shares to float, a decided departure from their now-fixed $1 a share benchmark, a change that would be sure to chase off investors seeking a safe, predictable return that these types of funds offer.

Here are Morningstar's selection of

seven stocks that have "wide moat" properties

in inverse order of their share-price appreciation this year:


St. Jude Medical


Company profile:

St. Jude Medical makes cardiovascular medical devices, including the world's most widely used mechanical heart valve. Its products include tissue heart valves, pacemakers and implantable cardiovascular defibrillators.

Investor takeaway:

Its shares are up 25% this year and have a three-year annualized return of almost 7%. Morningstar has a $49 price target on its shares, a 30% premium to the current price.

Morningstar says St. Jude Medical has "taken the lead in certain therapeutic areas," underscoring its wide moat status, which it originally earned for its cardiac devices. Analysts give its shares four "buy" ratings, one "outperform," and six "holds," according to an analysts survey.



(ADSK) - Get Report

Company profile:

Autodesk is the leading vendor of computer-aided design software worldwide.

Investor takeaway:

Its shares are up 24% this year and have a three-year annualized return of 30%. "Its strong competitive advantage, coupled with a sound business model, leaves the company well-positioned to benefit from a more stable economic environment," says Morningstar. Analysts give its shares five "buy" ratings, one "outperform," and two "holds."


Federated Investors

(FII) - Get Report

Company profile:

Federated Investors provides asset management services for institutional and individual investors. Mutual funds represent around 85% of the firm's assets under management. It's a big player in the money market fund arena with $285 billion in such assets at the end of 2011.

Federated Investors has seen run-off in those assets due to low rate, and now it faces the challenge of new Securities and Exchange Commission regulations that is seen hurting money fund managers by costing them more to manage.

Investor takeaway:

Its shares are up 19% this year (although they fell 5% last week), and have a three-year annualized return of 2.3%. The firm has been a big money market manager and so has been whipsawed by rate declines that have led to investor withdrawals, but Morningstar says "we think that the worst of the outflows are behind Federated and expect the firm to continue using its position as a top domestic manager of money market funds to expand both the depth and breadth of its operations."

But Federated Investors may face new challenges as the SEC is proposing changes to money market funds regulations that call for more capital contributions on the part of fund managers. Its shares yield a hefty 5.41%. Analysts give its shares two "hold" ratings.


Capella Education

(CPLA) - Get Report

Company profile:

Capella is a regionally accredited, exclusively online post-secondary education company. It offers bachelor's, master's, and doctoral programs.

Investor takeaway:

Its shares are up 23% this year, but have a three-year annualized loss of 8%. Morningstar says "With high demand for education, price-insensitive customers, minimal investment requirements, government-aided pricing, and a solid industry position, Capella possesses a wide economic moat, in our opinion." Analysts give its shares three "buy" ratings, two "holds," and one "underperform."



(CAT) - Get Report

Company profile:

Caterpillar is the world's largest maker of heavy construction equipment, including bulldozers, excavators, and loaders. It also produces engines for its own off-highway vehicles and others' machines.

Investor takeaway:

Its shares are up 24% this year and have a three-year annualized return of 56%. Its top markets, especially mining, are booming internationally, particularly in Asia, and its strong brand name usually makes it a top choice. When construction picks up domestically, it will do even better. Analysts give its shares one "buy" rating and four "holds."



(AB) - Get Report

Company profile:

AllianceBernstein, with $406 billion in assets under management, offers investment management services to institutional, retail, and private clients. Its products include mutual funds, hedge funds, and separately managed accounts.

Morningstar said its wide moat characteristics include "a meaningful amount of assets under management, a diverse mix of assets, and broad distribution by channel and geography."

Investor takeaway:

AllianceBernstein's shares are up 10% this year, even after losing 13% last Friday alone, after the company reported a nearly $200 million fourth-quarter loss and a steep drop in revenue. That's because its clients continued to withdraw money from stocks as they turned risk-averse because of the market volatility throughout 2011, the company said.

Its shares have a three-year annualized return of 5.5%. They get two "hold" ratings from analysts.


Weight Watchers

(WTW) - Get Report

Company profile:

Weight Watchers is a weight-management company with operations in more than 25 countries. Consumers buy more than $4 billion of Weight Watchers-branded products each year, and every week approximately 1.8 million people attend Weight Watchers meetings worldwide. The company encourages healthy weight loss through exercise, nutrition, and portion control.

Investor takeaway:

Its shares are up 36% this year and have a three-year annualized return of 55%. Morningstar says "the company benefits from a wide economic moat because it would be extremely difficult for a competitor to replicate the company's brand recognition and meeting infrastructure to compete against Weight Watchers in a significant way."

Weight Watchers gets three "buy" ratings and two "holds" from analysts.

S&P lowered its rating on Weight Watchers to "sell," from "buy," on Feb. 9, due to its valuation. The company's share price of $77.37 exceeds S&P's price target of $67, although S&P said that "long term, WTW should benefit from the rise in obesity in the U.S. and abroad, as well as on-line subscriber growth and an increase in male subscribers."

>>To see these stocks in action, visit the

7 Stocks With Double-Digit Retruns This Year

portfolio on Stockpickr.

Disclosure: TheStreet's editorial policy prohibits staff editors and reporters from holding positions in any individual stocks.