With the S&P 500 down some 45% since the start of 2008, many wary investors have been turning to the safety of dividend-paying stocks. In just the last three months of '08, domestic dividend-focused ETFs that invest in high-yielders like AT&T (NYSE:T) and Chevron experienced net inflows of $1 billion.

Dividends help to smooth out volatility, and as Jeremy Siegel notes, they're especially attractive during down markets, when their yields rise. Research by Professors Fuller and Goldstein supports his findings: the duo calculated that from 1970-2000, dividend-paying stocks outperformed non-dividend-paying stocks during market declines by an average of 1% to 1.5% per month.

But there's a catch
Even the most careful income-seeking investors were probably burned by the Great Dividend Implosion of 2008. According to data from Capital IQ, some 370 companies cut their dividends last year, for an average return of negative 56%. And we're not just talking dividend upstarts like Whole Foods (NASDAQ:WFMI), which first instituted a dividend policy in 2004. Many cutters were stalwarts -- Dow Chemical had consistently raised or maintained its dividend since 1912, before reducing its payout in February of this year.

So how can you tell if your company is about to make a cut? In an article last month, I called out General Electric (NYSE:GE) and Calumet Energy as risking dividend cuts. (GE announced a cut the following week, while Calumet has yet to do so.) Among the warning signs I pointed out:

  • High yields
  • High payout ratios
  • Industry headwinds

Extremely high yields signal investors' skepticism that the company will be able to maintain its dividend. A high payout ratio -- particularly when combined with a difficult operating environment -- suggests that the company doesn't have enough free cash flow to support the payouts.

But these factors don't necessarily imply that a cut is imminent. While GE made the right call in an effort to preserve capital, many other companies have continued to pay dividends they cannot afford for years, damaging their own firms -- and the value of your shares -- in the process.

I'll spare you all the details
A fascinating 2004 survey explains how and why. A team of four professors from Duke and Cornell surveyed more than 400 financial executives, discovering that 94% of executives "strongly ... or very strongly ... agree that they try to avoid reducing dividends." Many admitted to selling assets, laying off employees, borrowing heavily, or omitting important projects before cutting dividends.

See, these managers know that the market reacts negatively to dividend cuts. Several executives noted that Wall Street's response is an especially important consideration during liquidity crises -- such as the present one, which has hurt even strong banks such as Wells Fargo (NYSE:WFC) -- because they wouldn't want lenders to think their company is struggling. Such a fear may be one of the reasons why Citigroup (NYSE:C) reluctantly slashed its dividend three times, apparently hoping each time that a small cut would do the trick. It may also explain why Morgan Stanley could refrain from cutting its payouts, even after JPMorgan's (NYSE:JPM) recent cut opened the door for it to do so.

But let's get back to payout ratios. Unfortunately, if a company isn't generating enough free cash flow to support its payout, the extra cash has to come from someplace else. Aside from raising revenue or cutting expenditures, there are four basic ways a company can collect the cash it needs to make such payouts:

  • Burn cash
  • Borrow money
  • Issue shares
  • Sell assets

And while some of these practices may be acceptable band-aids for a difficult year, none are sustainable over the long term. A company that pursues these strategies for too long will eventually burn itself out, damaging its shareholders in the process. Even worse, it's likely that the company will ultimately have to cut its dividend anyway.

So which companies might fit that description today?

Three companies risking a burnout
These three companies have paid out more in dividends than they took in as free cash flow (or were free cash flow negative) over the past three years:

Company

Net Income Payout Ratio, 2008

Free Cash Flow Payout Ratio, 2008

Total 3-Year Shortfall*

Primary Funding Method

FPL Group

44%

N/A

$8.8 billion

Debt

Dominion Resources

50%

N/A

$8.0 billion

Sell Assets

Nordic American Tanker (NYSE:NAT)

135%

265%

$524 million

Issue shares

Data from Yahoo! Finance and Capital IQ, a division of Standard & Poor's.
*Calculated as total dividends paid minus free cash flow.

While FPL and Dominion may appear to have adequate net income to cover their dividends, it's important to remember that net income is an accounting construction that doesn't always reflect how much cash a company actually has left over to cut your check. Free cash flow payout ratios often provide a more accurate picture. In recent years, both companies have operated with free cash flow deficits.

FPL needed to borrow heavily to fund an increased dividend, even as it spent billions on new wind power plants. Dominion Resources has recently sold off billions in assets; it's been largely free cash flow negative, yet it has continued to pay its large dividend.

Nordic American doesn't pay a set dividend -- it distributes cash to shareholders based on its net operating cash flow -- but over the past five years, the company hasn't had a single year in which free cash flow outstripped the amount of cash paid to shareholders.

To his credit, Nordic American's CEO is honest about his company's strategy of supporting large dividend payouts with massive share issuances. As he recently told my colleague Mike Pienciak, "Given that Nordic American pays out all earnings as dividends, a growth model that relies on retained earnings is not right. Rather, Nordic American will continue to go to the capital markets." But that seems a little like the company is paying the left hand with the right hand, and the right hand with its foot.

The silver lining ...
Dividend stocks have a history of putting money in investors' pockets, but choosing the right dividend stocks for a down market is critical to protecting your portfolio. Paying close attention to how your company funds its dividend will help you achieve the golden returns dividends offer.

If you'd like to see the stocks our team at Motley Fool Income Investor likes, including their six "Buy First" dividend payers, you can try the service free for 30 days. Click here for all the details -- there's no obligation to subscribe.

Ilan Moscovitz owns shares of Whole Foods, a Motley Fool Stock Advisor recommendation. The Motley Fool has a disclosure policy.