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For retired investors, security is key. While building and maintaining wealth is your focus, you shouldn't take on high levels of risk throughout your portfolio. Stocks that offer steady income are among the best investments for retirees, while those that offer growth on top of dividends can provide an even sweeter opportunity to build wealth. With those qualities in mind, here are three stocks you should consider buying if you're retired. 

Dividends and growth

GE Total Return Price Chart

GE Total Return Price data by YCharts.

This is an easy one, but perhaps for reasons that aren't so obvious. Sure, General Electric Company (GE -5.64%) is well known among investors for consistent innovation and a formidable dividend yielding over 3%. It operates in nearly every industry you can name, from power generation to life sciences to aviation, and surely isn't going to lose its edge anytime soon. 

But beyond the obvious reasons that make General Electric standout as a secure investment is one that most draws me in: The $261 billion company often acts like a start-up. Management recently announced that all new hires in their 20s will learn how to write software code, which demonstrates that the company is tuned into the importance of digital trends. Of course, as the pioneer of the industrial internet -- which could add $10 trillion to $15 trillion to the global economy by 2035 through efficiency and productivity gains -- that shouldn't be all too surprising.

General Electric is well positioned to capitalize on opportunities in several industries that will be integral to the future economy. It's among the leaders in offering life sciences products critical to biotech R&D. It manufactures the best wind turbines in the world. The Harriet is the world's most efficient natural gas turbine -- and at 500 MW, it's also among the largest.

The PRISM, the world's most advanced Generation IV nuclear reactor in development, is capable of consuming used nuclear fuels, and is equipped with a "meltdown proof" passive safety design. It's also much smaller than traditional nuclear reactors, which will enable significant cost savings for future power-plant operators.

Simply put, General Electric offers a rare combination of safe income and growth. 

Buy 'em when they're down

ECL Total Return Price Chart

ECL Total Return Price data by YCharts.

A quick visit to the Ecolab (ECL -0.52%) website will put you in front of the following quote: "Ecolab share performance has exceeded the S&P 500 in 21 of the past 25 years, rising 4,206% compared with the S&P 500's 519% increase." If that's not the definition of growth, then I'm not sure what qualifies. You could argue that the company's growth will slow as it gets larger, but with a market cap of $33 billion and a management team that isn't shy about making splash acquisitions, I wouldn't call Ecolab a stale company. 

Similar to General Electric, Ecolab is smack dab in the middle of globally important industries. The company's technology aids in production of 40% of the world's crude oil, or nearly 35 million barrels per day. While the ongoing supply glut has resulted in a bit of a slowdown for Ecolab's oil production business, it's important to acknowledge that oil will continue to play a critical role in the global economy for decades into the future. Demand for ground, marine, and aviation fuels continues to grow, while dozens of chemicals will continue to be produced from fossil feedstocks for the foreseeable future.

In addition to operating in the energy production, water treatment, papermaking, food safety and inspection, and sanitation industries specifically, Ecolab also offers solutions and services that span multiple industries. For instance, more efficient cooling-water technologies can be applied to chemical manufacturing and beer manufacturing alike. 

A dividend yield hovering near 1.2% isn't earth-shattering, but it has grown 204% in the last 10 years. Although growth has hit a slight rough patch in 2016 with currency headwinds and a slowdown in oil drilling, Ecolab management expects growth to return to historical levels within the next several quarters. 

Under-the-radar growth play

CBM Total Return Price Chart

CBM Total Return Price data by YCharts.

Not paying a dividend makes Cambrex Corporation (CBM) the outlier of this group, but so do its growth prospects. The $1.5 billion company isn't a household name, and probably never will be. However, it's well positioned to take advantage of a growing trend in the pharmaceutical and biopharmaceutical industries: the desire of drug companies to outsource manufacturing.

Think about it. On top of conducting expensive R&D and running expensive clinical trials and marketing newly approved drugs to doctors and patients, drug companies have to navigate the complex and strict regulations of drug manufacturing. It's an expensive, but historically necessary, part of being a drug company. 

Cambrex Corporation is part of a growing niche of companies that changes this expensive endeavor for pharma companies by investing in specialized manufacturing facilities capable of producing dozens of active pharmaceutical ingredients under a single roof. Drug companies can avoid all of the headaches of manufacturing by outsourcing it to Cambrex Corporation, which makes guaranteed margins and has every incentive to reduce manufacturing-related expenses further to boost profits. 

While the stock has been among the top performers in the last five years -- returning over 1,000% -- the trend of outsourcing drug manufacturing is just heating up. That will allow Cambrex Corporation, which manufactures over 100 products today, to grow annual sales at a 10% clip for the foreseeable future. And with recent investments in its state-of-the-art facilities, management is eyeing pretty favorable long-term growth.

What does it mean for investors?

General Electric offers a rare combination of income and growth. Ecolab may be in a bit of rough patch (which really only equates to sideways growth) now, but its long-term focus should be appetizing for investors. And while Cambrex Corporation doesn't offer a dividend, it has plenty of room for growth ahead. If you're retired and looking for a mix of investments that offer security, income, and growth, then the list above provides three stocks you should consider buying.