Premier Investments, helmed by industry powerbroker Solomon Lew, is pressing Myer for more answers.
Lew executed a share raid on Myer stock in March, snapping up a 10.8% stake in the department store.
Premier has issued a statement regarding Myer's investor strategy day on November 1, as well as recent converage on Myer chairman-elect Garry Hounsell.
Hounsell said he is committed to the New Myer strategy and that there is evidence of "green shoots" in Myer's performance.
"Premier believes Myer needs to fully inform the market of its Q1 sales and profit performance at its strategy day so that the market can determine whether there has been any progress made in addressing the sales and profit decline at Myer," the Premier statement said.
"Q1 will have closed by the time of the strategy day, so there will be no need for any delay in releasing these numbers.
"Premier will also be examining whether there are any changes to the New Myer strategy announced at the strategy day in light of the chairman-elect's comments that he is committed to the New Myer strategy."