The insurance giant, which gave free shares to 94,000 customers in Ireland, made several attempts to contact the missing policy-holders. Their unclaimed shares will be held in trust for ten years, after which they will be sold and the money given to charity. It is not known how many of the missing policy-holders are Irish.

Weak stock markets will cut the issue price to 230p ( 3.50) a share, towards the bottom end of expectations, when trading begins in the morning. Standard Life initially indicated that Irish customers could expect windfalls of between 730 and 1,450. But the 230p launch price means their shares will be worth only 637- 1,266.

More than 1.5bn of the free shares will be sold immediately, although they will be snapped up by 300,000 Standard Life customers and staff who applied by last week's deadline to buy shares at a special discount. The average application was for 6,840 worth of shares, although the level of interest from the 130,000 Irish people eligible for the discounts is not known.

The discounted price has been set at 218.5p, giving someone who applied for the minimum 1,520 package a holding of 457 shares.

Because demand exceeded supply, only those who applied for up to 3,040 of shares will get everything they asked for.

Applications above that value will be allocated shares up to 70% of the value subscribed for, with a maximum allocation of 76,000.

In addition to the discounts and free shares up front, shareholders are in line for one loyalty share for every 20 shares they still hold a year from now.