The "offshore earners" – as they are referred to by Goldman Sachs – have generally been a winner so far for those who have piled in early enough, outperforming the broader ASX 200 by a factor of four this year with a return of close to 20 per cent.

Some of the old faithfuls among the offshore earners include Ramsay Health Care, packaging group Amcor, Cochlear and sleep device maker ResMed.

However, if the herd is all going the same way in buying up the stocks that generally perform well as the Australian dollar drops, eventually those stocks become too expensive on a price-earnings multiple basis. The wild card is the Australian dollar itself, trading at about US73¢. It's lost about 23 per cent over the past 12 months, and has come down 34 per cent since a peak of $US1.10 in mid-2011.

Many experts believe the currency won't fall much further and its natural level is about US70¢ in the low growth and weak commodity prices environment.

But what if Reserve Bank of Australia governor Glenn Stevens is granted his wish and the volatile forces in financial markets combine and it slips substantially lower?

In early April 2001, it was languishing at US48¢. That was at a time when golfer Tiger Woods won his second US Masters and there was no inkling of any future off-course indiscretions; the first series of Big Brother aired on television in Australia; and fugitive businessman Christopher Skase was still alive, and several months away from meeting the Grim Reaper on the Spanish island of Majorca.

Companies need to be managed well and have solid long-term growth prospects to keep attracting support from investors, because without that, a big kick from a falling Australian dollar isn't going to be much use.

Limited downside in the $A

Goldman Sachs head of portfolio strategy Matthew Ross last week had a close look at the offshore earners and came up with a basket of stocks where valuations were the most stretched, once three-year forward earnings forecasts were factored in.

He sees limited downside in the Australian dollar from here, and expects it to be about US67¢ in 12 months.

So the offshore earners – however impressive their management may be – that could be considered expensive include Ramsay Health Care, Cochlear, Iress, ResMed, Sonic Healthcare, Amcor and James Hardie Industries.

So where does the value lie for those who are convinced the falling Australian dollar is still a formidable theme in investment markets?

The Goldman Sachs group of offshore earners with better valuations included Incitec Pivot, Bluescope Steel, insurer QBE, Orica, standards group SAI and share registry business Computershare.

Macquarie in early July came up with a list of stocks. These, historically, are good performers when the Australian dollar is dropping, and also are relatively safe with low levels of volatility.

They included CSL, Ramsay Health Care, Amcor, AusNet Services and Telstra.

On the flipside, its basket of stocks which historically perform poorly when the Australian dollar is falling and have high volatility was made up of Flight Centre, Transpacific, Challenger, Fortescue Metals and Bluescope Steel.

Picking solid long-term winners is a tough game, and the currency can shift substantially.

In highly volatile times, the "defensive" stocks are also highly sought-after and with the twin combination of being a prime defensive stock from running private hospitals and also being a substantial offshore earner, investors in Ramsay Health Care have cleaned up with the company's share price climbing from $15 to about $65 in just four years.

Interestingly, when the Australia dollar was in the doldrums at just US48¢ in early April 2001, the ASX 200 index was sitting at 3194 points.

The top 10 stocks at the time – 14 years ago – are remarkably similar to the top dogs on the ASX now. The big four banks are all there. However, it was National Australia Bank that was top of the pile ahead of Commonwealth Bank, and resource sector favourites BHP and Rio were nestled among them, preparing to ride a resources boom that few had predicted.

Aside from some classification issues around whether the likes of Rupert Murdoch's News Corp should be included, or the Optus owner then known as Cable & Wireless Optus, the names are very familiar and also include beer maker Foster's Group.

The top 10 now doesn't differ much, which some experts say shows a worrying lack of entrepreneurship, particularly in the technology sector where in the United States the top companies now include Google. It was established as a private company in 1998 by budding entrepreneurs.