Fletcher Building's place in a key sharemarket index is due to be decided today.

Mark Lister, head of private wealth research at Craigs Investment Partners, said the announcement of Fletcher's place in the MSCI Index is due out today and we will know the result tomorrow.

The building materials and construction giant could be replaced by The a2 Milk Company, he said.

Read more: Fletcher price slide sparks fears of index and investor exit


The index, launched in 1987, is designed to measure the performance of the large and mid-cap segments of the New Zealand market. Seven companies are in it, covering about 85 per cent of the free float-adjusted market capitalisation in New Zealand.

"The long-awaited and eagerly anticipated semi-annual MSCI index review announcement is due on Monday," he said.

New Zealanders will not learn of any change until around 9am tomorrow morning, he said, because "it is set for release at about 5pm US eastern time on the 14th".

"The focus in recent weeks has centred on the likelihood of a2 Milk joining the MSCI New Zealand and MSCI World indices, potentially at the expense of Mercury [Energy] or Fletcher Building. There is also a good chance that Xero joins the MSCI Australia and MSCI World indices. The changes will be effective 1 June," Lister said.

If Fletcher left the index, passive investors who use it to benchmark investments might sell their shares, resulting in further price reductions as those institutions dump the stock.

David Price, a broker at Forsyth Barr, said last month that Fletcher was trading at its lowest price since March 2009. There were concerns about the potential for the stock to fall out of the MSCI New Zealand Index at its next rebalancing, to be replaced by a2 Milk Co, which is trading at nearly $13.

Fisher & Paykel Healthcare, Spark New Zealand, Auckland International Airport, Ryman Healthcare, Fletcher, Meridian Energy and Mercury Energy are in the index, giving a sector weight of around 34 per cent in healthcare, 18 per cent in telecommunications, 17 per cent in utilities, 17 per cent in industrials and 12 per cent in materials.

Fletcher's share price recovered somewhat lately, moving from $5.53 on April 4 to $6.30 last week. The a2 Milk Company was trading at $12.96 on Friday.