Shareholders have won the first class action lawsuit to go all the way to judgment in Australia – but are unlikely to see a cent from defendant Myer because the stock market didn’t believe inflated profit forecasts made by the retailer’s chief executive, a judge has found.

The landmark judgment, handed down on Thursday by the federal court, is likely to be of more help to shareholders in future lawsuits, because judge Jonathan Beach accepted that it was not necessary to prove Myer misled every investor individually.

Instead, drawing on a journal article he wrote while a barrister, Beach found that it was enough to show the market at large was misled.

Shareholders in the case, which was organised by the Melbourne solicitor Mark Elliott, alleged Myer misled the market in September 2014 when its then CEO, Bernie Brookes, told analysts and journalists the company’s profit would be higher in the 2015 financial year than the $98.5m posted in 2014.

But in March the following year the company admitted profits for the 2015 financial year would probably be down on the previous year, at between $75m and $80m, because of stagnant sales and soaring costs.

Myer’s share price immediately fell more than 10%.

Beach found Myer engaged in misleading and deceptive conduct by failing to correct Brookes’s statement on multiple occasions between September 2014 and March 2015.

But the judge said he was “not convinced that the applicant and group members have suffered any loss flowing from such contraventions” because Myer’s share price “already factored in an NPAT [net profit after tax] well south of Mr Brookes’s rosy picture painted on 11 September 2014”.

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“In other words, the hard-edged scepticism of market analysts and market makers at the time of the contraventions had already deflated Mr Brookes’s inflated views,” Beach said.

“So any required corrective statement that should have been made at the time of the contraventions, if it had been made, is likely to have had no or no material effect on the market price.”

However, Elliott told Guardian Australia he would now ask for access to the Myer share register so that he could write to shareholders “and invite them to individually prove their loss”.

“That’s the upshot of the decision and it’s a slog but very doable,” he said.

“We have registered 1,200 [shareholders] already and expect double that easily.”

In a victory for class action lawyers and potential plaintiffs, Beach said he accepted the theory of “market-based” or indirect causation, where harm is done to investors because the price of securities they buy is inflated by incorrect information.

This is significantly easier to prove than showing that an investor directly relied on the misleading statements made by the company when deciding to buy shares.

The rosy picture painted by Brookes evaporated within weeks, evidence before the court shows.

By 30 October 2014, internal Myer forecasts predicted profit would be at most $95m, and could be as little as $84m.

And a few days later, on 2 November 2014, Brookes sent an email to the board titled “The Good, The Bad and the Ugly” in which he said that despite good recent sales figures, the overall picture was “‘ugly’ and even with $6m of cost reduction we will need the ‘sales start’ to the quarter to continue”.

By this time Myer’s internal profit forecasts were 5% more than those of analysts, Beach said.

“But instead of announcing anything to the market, despite all of the negative news in the first quarter of FY15 and its internal profit projections showing the unlikelihood of FY15 NPAT above $90m, Myer appears to have thereafter created a series of internal profit projections which ‘targeted’ profit figures at the same level as the budget had originally proposed in July 2014,” he said.

Myer’s share price has continued to fall since 2015 amid continuing consumer gloom.

Shares that changed hands for about $1.70 in mid-2015 closed at 10c on Thursday.

“As this matter relates to historical events and may be appealed, Myer will not provide any further comment on the judgment,” the company said in a statement to the ASX.