Two distinct groups of investors have emerged since the U.S. stock market rally began in early March. Initially overly cautious and smug in their desire to protect themselves, the first group of investors were convinced the rally was going to sputter and stall. It hasn’t, and 57% later these investors now believe they’re getting left behind, so they’re piling into the key indices in effort to make up lost ground.

The second group consists of investors who believe they can outsmart the market. They’ve stayed on the sidelines, planning to buy in and make their fortunes when the markets break down a second time. But they may never get their chance.

Both strategies are flawed. And both ignore the single strategy that investors need to employ to profit in the later stages of a recovery rally.

The first group of investors – the indexers – has a unique problem. Broad-based investments such as indices are really only favored in the early stages of any recovery rally, when there’s plenty of easy money to be made.

These investors either don’t know – or choose to ignore – the reality that long rallies tend to change character: Broad-based choices are super when the rising tide is lifting all boats early in the game. But then the game itself changes.

Early on, index investors reap the lion’s share of the market-rally profits. But as rallies mature and capital continues to flow, successful investing becomes more of a stock-picker’s game. This means that specific stocks – not the indices – become vastly higher probability bets.

There are many reasons why this shift occurs, but it really comes down to two key factors: Where the money is going, and where the money is flowing.

This means there’s plenty of fuel to keep the rally alive both here and abroad, and we’re not alone in our opinion.

Beware of the “Golden Period”

Jack Ablin, who helps oversee $60 billion as chief investment officer for Harris Private Bank, says there is still “an enormous stockpile of liquidity on the sidelines [and] the reinvestment of [that] cash could help fuel the market.”

Unfortunately, this is well-known to investors, which actually makes it a problem. As hedge-fund manager Kyle Bass noted: “We are today in the midst of what economists often refer to as the ‘Golden’ period, where everything feels good and the long-term effects of deficit spending and money printing have not yet been realized.”

This is something I’ve talked about time and again during investor presentations all around the world. People who are already numb from having been pummeled on the way down, have once again become intoxicated with the rally over the 12 – 18 months that such advances typically last. They see a chance to recoup all their losses and be made whole. This makes them more prone to poor timing decisions, or poor investments choices.

Another problem with long rallies like the one we’re experiencing now is that you have be “in” from the get-go or you won’t “go” at all. Today’s algorithmic trading simply doesn’t allow for the kinds of market pullbacks and corrections we used to see as recently as 10 years ago. I know – I’ve written several of these trading programs. Today, if you’re not in when the money starts moving, you might as well hang it up.

At the same time, you just can’t sit and wait until things get better, either. If you do, you are likely to miss most of the gains.

And don’t bother trying to “time” the market. That’s a recipe for disaster, as reflected by numerous Dalbar studies. The Dalbar data repeatedly demonstrates that investors who try to time the markets not only fail miserably in the near term, over a period of years they tend to fall dramatically behind the market averages.

How much behind? Try 40%-60%, depending on what data period is examined.

Winning markets – Big and small

That brings me back to today’s key point. In the early stages of a rally, it’s best to invest using broad, sweeping choices like index funds or exchange-traded funds (ETFs), which are tied to the major indices. Believe it or not, picking the “right” stocks is essentially irrelevant. Sure you always want to have some zoomers in your portfolio, but when the rally really begins, it’s far more important to have broad-based stock-market exposure. It’s a shotgun approach. And it works.

Over the past 118 years, there have been 19 bear-market events in the Dow Jones Industrial Average. The average bear-market drop was 37%. The rally into the next year generated an average gain of 40% from the market bottom – with 70% of the gains coming within the first half of the rally’s duration.

That’s why, for example, I’ve repeatedly told Money Morning readers, as well as subscribers to our affiliated publications, to employ such broad choices as the Vanguard Wellington or the SPDR S&P 500 ETF (NYSE: SPY, Stock Forum).

Today, with the Standard & Poor’s 500 Index having zoomed 57% from its March 9 low, the rebound is 1.5 times bigger than the typical post-recessionary rally.

That means the best choices are now the companies that are backed by trillions of dollars in stimulus spending and that operate in growth markets that support real earnings, real cash flow and real purchasing power.

That makes a lot of sense if you think about it. Fully 78% of the world’s total economic activity now takes place outside U .S. borders, which means that if you really want to “follow the money,” you’ve got to look in areas that you might traditionally have considered as “off limits.” In fact, you may find that you are looking at companies whose names you can’t easily pronounce. But many of those companies not only have double- or even triple-digit growth, they are still viewed as compelling values – because of the torrid growth rates of the markets they sell to.

Take Iceland. After its financial travails, the country once again has positive gross domestic product (GDP) growth. Its unemployment rate of 7.7% is not only dropping, it’s now well below the U.S. jobless rate of 9.8%.

Iceland was the first nation to have its currency destroyed and its finances and political government replaced. It embraced its pain, and focused on doing what was necessary to fix its issues. Now its exports are booming, and its outlook is much better than it was just a few months ago.

Iceland has turned into an example of growth following a situation that most people thought was unfixable. From September 2008 to August 2009 – a period in which most economies were shrinking –the Icelandic economy actually expanded 2.4%. For global investors, economic growth – in the face of some of the toughest economic issues in generations – is the Holy Grail in surviving an economic crisis.

Tourism is flourishing in Iceland, as international citizens flock to that country’s shores to enjoy having a strong currency to spend.

Icelandic vocalist Bjork, 32, a former fashion model wearing silver snakeskin leggings, black boots and blond ponytail, recently told a journalist that “business is growing.” Thanks to the utsala – “SALE” – signs that were everywhere, “tourists are buying a lot these days, and even Icelanders are buying more at home.”

Granted, shopping for designer duds in Iceland with a snake-skinned model may not be your notion of a conservative-economic recovery play, but don’t miss the real point here: What Bjork was shrewdly observing was that consumers in her part of the world are no longer panicking. They’re back from the brink of almost-total collapse and have now come to terms with their nation’s economic recovery.

This demonstrates just why investors need to be looking at markets where there is real growth – from the smallest economies like Iceland, to some of the largest – such as China.

Speaking of which, with a population of 1.3 billion, a personal savings rate of 35%, and a government that isn’t suffering from a fiscal hangover, it’s no wonder the world’s leading companies are beating a path to the Red Dragon’s doorstep.

In China, the government’s focus is growth, and banks are looking for projects to invest in. Those in positions of power and authority understand the need for balancing savings, growth and long-term investments. China’s stimulus plan focuses on infrastructure development, which will generate long-term growth, while the United States had had to use its balance sheet to prop up “zombie banks” – just to keep things from getting worse than they already are.

If this sounds a bit complex, the reality is that it’s actually quite basic. Limiting yourself to index investments at this stage of the market cycle is not your best bet. We’re now at the stage where the world’s stock markets have already delivered the broad, indiscriminate gains that benefit index-investors to more specific opportunities that require more-careful analysis and some specialization. Follow that game plan and you’ll be a long-term winner.

Read more Stockhouse articles by Keith Fitz-Gerald