The Top 1,000 magazine, published with The Irish Times today, inadvertently fails to list Pfizer, the international drugs and healthcare group, which employs more than 4,000 people at eight operations in Ireland.

The exclusion was due to a difficulty in assessing the scale of the company’s business in Ireland.

Pfizer has more than 40 registered entities in Ireland, many of which have their accounts consolidated in the reported figures of CP Pharmaceuticals International, based in the Netherlands.

Pfizer, which should be ranked the seventh-largest business in Ireland, appears correctly in the online database of the top 1,000 companies in Ireland ( top1000.ie), which went online this morning.