Image: A sign stands in front of the Wal-Mart Stores Inc. headquarters in Bentonville, Ark. © April L. Brown,AP

After the stock market lost 20% of its value in October 1987, Sam Walton, then one of America's richest men, was unfazed.

In less than a week, the value of his shares of Wal-Mart Stores (WMT, news) shed almost $3 billion, reducing his wealth to a mere $4.8 billion. "It's paper anyway," he told The Associated Press. "It was paper when we started, and it's paper afterward."

Given the wrenching swings of the past few weeks, many of us may wish we could be so sanguine about our own losses. But even if we don't have a few extra billion dollars in the bank, there are useful lessons we can glean from the way the Waltons and other ultrarich families cope with investments and market volatility.

Just like us, the rich want to maintain their lifestyle, preserve wealth and have money for their heirs or philanthropy. And when it comes to investing, there are several ways the rest of us should take a cue from them:

The very wealthy have a plan. Sam Walton's plan started in the early 1950s, when, on the advice of his father-in-law, he set up a family partnership, made up of him, his wife, Helen, and their four children, to own his two variety stores. By doing that, he began planning his estate and building family wealth years before he opened the first Wal-Mart in 1962.

Nowadays, most very wealthy people have a team of advisers and an investing strategy in place that should work even when the worst imaginable case becomes real. Small investors, too, should have a comfortable investment process that works in good times and bad.

A financial adviser can be invaluable in helping you with this, but so can a trusted family member or friend who will help you stick to your plan when you start to doubt it.

The very wealthy live below their means. Walton, who died in 1992, was famously frugal, driving an old pickup truck and flying coach. Many very wealthy people spend much more extravagantly, but even so, "most of our ultrawealthy clients have a lifestyle that is well below their means," says Craig Rawlins, the president of Harris myCFO Investment Advisory Services, which serves wealthy families.

When you don't spend everything, he says, "you have a better opportunity to weather this volatility because you know there's a cushion there."

The very wealthy value cash flow. One of the most painful lessons of 2008 was the recognition that we need to keep enough in cash or liquid investments to weather a stretch when the value of everything else is in flux. Martin Halbfinger, managing director, wealth management, at UBS, says every investor should have a "SWAN" account -- for "sleep well at night."

"That's a different number for every investor," he says, but you should have enough in bank accounts, bonds or other liquid investments that you can leave your stocks alone when market volatility defies logic.

Sturdy, dividend-paying stocks also can help. Annual dividends on the Walton family's 1.68 billion shares of Wal-Mart stock add up to $2.45 billion a year, enough to buy plenty of groceries and just about anything else.

The very wealthy focus on risk, not return. Larry Palmer, managing director, private wealth management, at Morgan Stanley Smith Barney, said he has never had a client say, "My objective is to have my family wealth beat the S&P 500." Rather, he says, clients focus on what kinds of risks they are taking with their portfolio.

The Walton family wealth has been long tied to its Wal-Mart stock, now valued at $83.6 billion. But Sam also bought the tiny Bank of Bentonville in 1961, and it is now part of the family-owned Arvest Bank, an $11.5 billion banking company. Walton Enterprises also owns a chain of small newspapers that, along with other interests, offers diversification and pushes the family's estimated combined wealth close to $100 billion.

Small investors need to manage their portfolios similarly, making sure that their holdings of stock and other volatile investments aren't so great that they are putting more at risk than they intended to.

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The very wealthy hang on. The super-rich don't sell because they are fearful, though some may be selling now for investment reasons, such as cutting the tax bite on holdings with big gains. The Walton family ownership of Wal-Mart stock hasn't changed since late 2002, when some shares were transferred to charitable funds.

In that sense, Sam was spot on. Although the Walton family's Wal-Mart shares have dropped by more than $10 billion since mid-May, until the stock is actually sold, the losses really are nothing more than paper.

This article was reported by Karen Blumenthal for The Wall Street Journal.