Sigma Healthcare’s $30 billion merger with Chemist Warehouse is expected to shake up the ASX, as it will reduce the weighting of other blue-chip giants that have long dominated the Australian sharemarket.

That’s according to strategists at Morgan Stanley, who estimate the index weight of the beefed-up Sigma could climb 50 basis points, generating $537 million worth of trades from index trackers that follow the S&P/ASX 200.