The plummeting iron ore price has wiped $74 billion from the value of Australia's key iron ore mining stocks since January 2014, and analysts expect share prices to continue their decline as the price for the commodity slides.

Investors that held on to the stocks while the price for iron ore sank during the past 15 months are now nursing losses in value of as much as 92 per cent.

Together, BHP Billiton, Rio Tinto, Fortescue Metals Group, Mount Gibson Iron, Atlas Iron, BC Iron, Arrium and Grange Resources suffered enormously as ore prices slumped 60 per cent from $US134 a tonne in January 2014 to $US50.93 a tonne on Friday.

A combined $73.7 billion, or 22 per cent of value, has been erased from their market capitalisations since January 2, 2014.

Excluding the diversified big miners, BHP Billiton and Rio Tinto, the combined market value of the six remaining companies has declined 71 per cent or $17.2 billion.

Junior Pilbara producers BC Iron and Atlas Iron have been hit the hardest by the market's reaction to the crashing price.

Atlas' market capitalisation has shed more than $900 million to hover near $110 million, and BC Iron has lost about 92 per cent of its market capitalisation in the past 15 months and is now valued about $51 million.

The two producers have been cutting costs in line with the falling price but for Atlas, the hard work has not been enough to keep it in production. Burdened by $327 million in gross debt, Atlas plans to gradually mothball its three mines this month to curb cash burn as it conducts a review of its business. Its shares have been suspended from trading since April 7.

Hartleys analyst Trent Barnett said the iron ore players had been savaged by the market.

"With the smaller players like BC and Atlas, there really isn't much market cap left to disappear," Mr Barnett said.

However, Goldman Sachs expects the market pain to continue for Fortescue.

A swath of analysts took a knife to their iron ore price forecasts last week, and Goldman was among the most bearish.

The bank's analysts downgraded their price expectations for the next four years to as low as $US40 a tonne and slapped "sell" recommendations on Rio and Fortescue, with a 12-month target price of 50¢ on the latter.

Fortescue shares are sitting near $1.87 but Goldman said its "new price deck significantly crimps the cashflow, and consequently FMG's large debt position continues to be a major issue".

Should Goldman's prediction come to fruition and the number of shares on issue remained at 3.1 billion, the company's market cap would fall to about $1.5 billion, from $5.8 billion at present.

The company's chairman, Andrew Forrest, is the miner's largest shareholder, with a 33.3 per cent stake. At 50¢ a share, Mr Forrest's holding would be worth just under $520 million, a far cry from the $13.6 billion the shares would have been worth at their peak in 2008.

Goldman slashed its average price expectations for 2015 and 2016 to $US52 and $US44 a tonne respectively, noting "new supply and lacklustre demand" meant the price was "unlikely to recover above $US50 a tonne again".

Citi lowered its expectations for the rest of the year to $US37 a tonne and crunched its longer-term forecasts to $US40 a tonne. Citi analysts don't expect the price to average above that level until 2019.

UBS downgraded expectations to $US50 a tonne this year and $US48 a tonne next year, while credit ratings agency S&P cut this year's forecast to $US45 a tonne and put BHP, Rio, Fortescue and other iron ore miners on review for ratings downgrades.

Allan Gray portfolio manager Simon Mawhinney said the iron ore market value erased in the past year needed to be viewed in the context of the "extreme value" created during the past 10 years, but there was likely to be "a significant amount of pain to come" for iron ore exposed stocks.

"Investors would be wise to be cautious, as would companies, to make sure the balance sheets in question are strong enough to be able to withstand conditions if the market deteriorates further," he said.

Mr Mawhinney said his fund's investment in Arrium was based on the value he sees in the company's mining consumables and steel businesses, rather than its iron ore business.

However, contrarian investors have increased their holdings in iron ore in recent months, including US-based fund manager The Capital Group.

The long-term fund took a substantial stake of 5.02 per cent in Fortescue in February and has since increased its holding to 7.08 per cent as of March 30, making it the miner's third-largest shareholder.