Timing matters. All too often investors succumb to the temptation to buy a stock that’s been a hot performer, only to get in when it’s about to go cold.

One market strategist says such a turning point is approaching fast for many dividend-paying stocks. They’ve been popular because dividend payers are frequently touted as a relatively low-risk investment option. “People who have been seeking safety will discover they really didn’t get what they thought they were buying,” says Seth Masters, chief investment officer with mutual fund company and asset manager AllianceBernstein.

Mutual funds specializing in dividend-paying stocks have attracted more than $60 billion in the US over the last three years. That number wouldn’t normally be impressive, except that cash has flowed in as investors pulled out of nearly all other types of stock funds.

Even so, Masters says it’s time to take a critical look at dividends. At a recent presentation in Boston, he told AllianceBernstein clients that buying these stocks at current prices could be much riskier than expected.

The concern is that the stocks paying the highest yields have appreciated more rapidly than most other stocks since the market hit bottom in 2009.

Masters cites data showing that these high-yielding stocks have gained so much that they’ve recently traded at a 50 percent premium to their historical average. That premium is calculated based on the average price-earnings ratio since 1951 for the 20 percent of stocks with the highest dividend yields. The P/E ratio divides a company’s stock price by the company’s annual earnings per share. A higher ratio suggests a stock is expensive because, in a sense, it takes more years of earnings for investors to get back they paid for it. A lower ratio suggests it is cheap.

Masters believes it’s only a matter of time before prices of those top dividend-payers get back in sync with the historic average. That means these stocks would eventually underperform other segments of the market.

Due the strong gains for such top dividend-payers, these stocks make up a greater share of the S&P 500 index than they did a few years ago. The highest-yielding dividend payers account for about 44 percent of the market cap of stocks in the S&P 500, up from an average 34 percent dating to 1970, Masters says. These stocks have gotten “extremely expensive,” he says.

By expressing concern over the current prices of the market’s top dividend payers, Masters isn’t suggesting stocks are overpriced generally. In fact, he sees strong potential, with stocks priced slightly below their historic average P/E ratio. Current risks abound, from challenges such as the so-called “fiscal cliff” to Europe’s debt crisis. But Masters says companies generally have modest debt and plenty of cash.

He sees the best current opportunity in value stocks, which he defines as stocks that are priced low relative to the book value of the underlying company. That’s the value of the assets on a company’s balance sheet minus its liabilities. While many value stocks pay dividends, not all do, and Masters sees an abundance of potential bargains in the group.

Stocks in the least expensive 20 percent of the S&P 500 based on price-to-book values are trading at a discounted level that’s comparable to the bargain-bin prices when stocks hit bottom in March 2009. “Cheap stocks are very, very cheap today, relative to any time in long-term history,” Masters says. “That makes them very compelling.”

But Masters cautions investors not to expect a big short-term gain from moving their money into value stocks. Markets can be so unpredictable in the short term that it’s hard to say when such an approach might pay off.

AP