Contact Energy urged the NZX to stagger its move to a 'free-float' method of calculating index weightings because of the negative impact on its stock.
NZX will switch to the new weightings in June, stripping out any large blocks of shares deemed not available for trading. As a result, Contact's weighting on the NZX 50 Index drops to about 4.58 per cent from 8.73 per cent, which is likely to trigger selling by index-weighted funds.
Contact is 52.8 per cent owned by Australia's Origin Energy, which the new NZX50 weighting system will ignore under a new approach to strip out cornerstone shareholdings.
Since March 14, shares of Contact have dropped 6.2 per cent while the NZX 50 edged up 0.1 per cent. The shares rose 0.4 per cent to $4.69 today and have dropped from $5.76 a year ago. They are rated 'outperform' based on the consensus of eight analysts in a Reuters survey.
Contact "understands NZX's rationale for the changes, but submitted that the weightings should change over four-to-eight quarters rather than at a single date," the Wellington-based company said in a letter to shareholders released today. Sales of the stock "are not being driven by pessimism about Contact."