This article has been republished to correct the headline. An earlier version incorrectly said that Johnson was predicting a 70% gain for stocks.

I couldn’t have picked a worse day to interview Craig Johnson, longtime bullish technical analyst for Piper Jaffray.

It was last Thursday, when the Dow Jones Industrial Average lost 317 points, and fears about Ukraine, Gaza, and Argentina’s default on its debt were paramount.

When we spoke late that afternoon, Johnson sounded a bit harried but otherwise unfazed. Just two days before, his team had published a new report, “2K and Beyond/ All Systems Go.” And on Thursday he wasn’t giving any ground.

Where to put your money when markets are in turmoil

True, the S&P 500 SPX, -1.11% had just broken below its 50-day moving average, signifying short-term weakness. (It has since gone even lower.) But that already happened twice this year, in February and May, and stocks kept moving higher, Johnson said.

“These sell-offs burn themselves out,” he added.

So, until there’s a deeper correction that drives the S&P below longer-term support levels around 1850, Johnson is giving this market the benefit of the doubt.

“The secular bull market is just starting,” he declared.

And not just any secular bull market, he said, but “a big, long, powerful secular bull market” that could last “multiple years in length and [earn] a multiple of your money.”

Raging bull

If you’re ready to throw rotten tomatoes at your computer screen, you’re not alone. Two years ago, Johnson was in a small, besieged bullish fraternity along with Laszlo Birinyi, Jim Stack, James Paulsen of Wells Capital Management, and fellow technician Mark Arbeter, then of S&P.

Clients called him crazy, and when this column first wrote about Johnson’s 2000 S&P call, the comments were downright contemptuous.

And yet, here we are two years later, and the S&P peaked at 1987.98 in mid-July. Johnson predicted the index would end 2013 at 1850. It closed at 1848.36.

Johnson may well have been lucky, but it was an astonishing call by any measure. The few investors who listened to him rather than to the gold bugs, hyperinflationists and doom-and-gloomers of every stripe have made a boatload of money. The S&P is up more than 40% since then.

But Johnson’s not done. One reason he thinks the market is heading a lot higher for a lot longer is that pessimism is still pervasive.

“People are scared. They still hate this market. They think it’s all manipulated by the Fed,” he said.

Trading volume is still weak, he said, and “it doesn’t feel like there’s a lot of individual investors participating today.”

That’s actually true: The small number of hyperactive traders at discount brokerage firms obscure the bigger picture that the vast majority of individuals are still too spooked to buy stocks. Study after study confirms that. Institutions aren’t exactly euphoric, either.

If Johnson is right, stocks will rally for a long time. He thinks we’re in the kind of secular (extreme long-term) bull market we saw in both the 1950s and the 1980s. Each of those runs lasted much longer than a decade.

“The secular bull market began in March of 2009 and was finally confirmed when we went through the 2000 and 2007 highs,” Johnson explained.

That “confirmation” occurred in March 2013, when the S&P 500 broke above 1550, its previous all-time peak.

“When you break out of big bases, the market accelerates,” he explained, and indeed, the S&P has gained as much as 28% since hitting that magic number.

Comparing that with 1952 and 1982, when the market also surpassed its previous high (in price only, not including dividends), Johnson said, “If history does rhyme, [this bull market] would last 10 years from 2013.”

“Investors made five times their money” after 1952 and 15 times their money from 1982 to 2000, he said.

Stocks for the long run

So, if you take March 2009 as your starting point and multiply by five, that would get us to S&P 3400 before it’s all over — about 70% higher than current levels. Yet over a decade, that’s a compound annual growth rate of less than 6% a year, which is not outlandish. (That’s just hypothetical, by the way: Johnson hasn’t published any official forecast beyond 2100 by the end of 2014. I’m not predicting that, either.)

But the continuation of the bull market, of course, depends on the economy and earnings. “Things are definitely getting better with the economy,” Johnson said. He thinks rising interest rates in years to come could actually facilitate a switch into stocks from bonds.

And since the price/earnings multiple of the S&P already has expanded, “we need earnings to come through.” So far this quarter, almost 70% of S&P companies that have reported earnings have beaten Wall Street estimates.

Still, Johnson conceded, “we’re overdue for a true correction. I would have thought it would have happened by now.” (So would I, and last week, I recommended that readers trim some of their positions to reduce short-term risk.)

Johnson’s definitely not advising people to dump stocks. In fact, he thinks a selloff is a buying opportunity.

He says investing in big-blue chip U.S. stocks is the way to go for most people. “Why not be a buy-and-hold investor?” he asked.

Why not indeed? If he’s right and this bull market has years to go, it would be a great boon for retiring baby boomers and others who were smart enough to keep at least some — but certainly not all — of their money in stocks, while everyone else was busy fighting the Fed.

Howard R. Gold is a MarketWatch columnist and founder and editor of GoldenEgg Investing, which offers simple, low-cost, low-risk retirement investing plans. Follow him on Twitter @howardrgold.

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