Investors’ aggressive reaction to electronic design software company Altium’s weaker-than-expected full-year guidance has sparked CEO Aram Mirkazemi to question how he conveys one-off costs to the market.

On Monday Altium shares slumped 5.9 per cent to close at $32.44, having fallen as much as 10 per cent earlier, after the company said its full-year underlying earnings before interest, tax, depreciation and amortisation (EBITDA) margin would be at the low end of its 34 per cent to 36 per cent guidance range.