You probably know all too well just how much damage the recent recession has done for people's financial health. But as more Baby Boomers enter their final work years with woefully insufficient retirement nest eggs, their actions could have huge implications for the health of many businesses going forward -- and have a big impact on shareholders in those companies.

It's going to happen
For many retirees, the question isn't going to be whether they'll run out of money, but when. Despite a recent report from Fidelity showing that the average 401(k) retirement plan balance hit an all-time high in the first quarter of 2011, that figure is less than $75,000. And even if we assume that those who are closer to retirement have somewhat higher balances than the overall average for all ages, research from the Employee Benefit Research Institute shows that a huge percentage of those approaching retirement have little or no savings.

In addition, the recession has had not only an immediate impact on workers' investment portfolios but also a much longer-term effect on their earning power. Because Social Security benefits and pension payments are based on average earnings, the weak wage growth that started during the recession has dampened previous increases in salaries, thereby reducing the amounts that workers will eventually receive in retirement. Researchers from the Center for Retirement Research suggest that the recession will cost workers an average of $2,300 per year after they retire.

Cutting corners
In response, retirees will have to cut corners on living expenses after retirement to a much greater extent than previously thought. Already, personal finance experts have started suggesting what would have been considered extreme measures just a few years ago to try to conserve cash in retirement. Among the suggestions are moves like finding another retired couple to share a house with, rent out all or part of a home in order to generate income, and share resources like vehicles and appliances to cut back on expenses.

That in turn will have an impact on businesses in many industries. For years, companies geared toward an older customer base have looked longingly at the demographic shift coming from aging boomers as a profit opportunity. If those hopes don't bear fruit, it could lead to some surprising results:

  • Health-care companies that provide actual medical goods and services, such as generic pharma leader Teva Pharmaceutical (Nasdaq: TEVA) and medical equipment maker Medtronic (NYSE: MDT), should see little impact as retirees can do little to change whether they'll need health care. But with little extra income, health insurers like WellPoint (NYSE: WLP) could see less revenue from high-tier Medicare supplement insurance, as broke seniors increasingly rely on government programs like Medicaid.
  • Many retirees wish to travel, but trips are a dispensable expense when you're having trouble making ends meet. That spells difficulty for travel industry leaders like cruise line Carnival (NYSE: CCL) and hotel operator Marriott (NYSE: MAR), both of which rely on older leisure travelers for a substantial part of their revenue.
  • Senior housing facilities have been a hot investing area as investors in Sunrise Senior Living (NYSE: SRZ) and Brookdale Senior Living (NYSE: BKD) anticipate retirees moving out of their homes. Yet with the housing market in disarray, more retirees may defer such moves, causing excess capacity for those companies.

What to do
You should take away two things from this trend. First and foremost, for your own personal finances, saving more now will help you avoid the fate that many retirees will face as they run out of money, having to rely solely on Social Security and other fixed income in order to survive.

But also, if you've invested in any stocks with the expectation that a rising Boomer population would bring more business, you should take a closer look to see if higher revenue is really in the cards. If a whole generation of retirees turns out to have less money than investors expect, it could throw shares for a loop -- and reward those who got out early.

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Fool contributor Dan Caplinger hopes you'll never go broke. He doesn't own shares of the companies mentioned in this article. The Motley Fool owns shares of Teva Pharmaceutical and Medtronic. Motley Fool newsletter services have recommended WellPoint and Teva Pharmaceutical. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Fool's disclosure policy always has something for you.