GUS has amassed 91 per cent of the group, overcoming ABI's legal challenge to the bid and ending any possibility of an eleventh hour higher offer from a competitor.
GUS will now be able to concentrate on winning another prized target: Argos, the catalogue retailer. Stuart Rose, Argos's newly installed chief executive, is embarking on a frantic round of meetings with institutional shareholders next week in an effort to thwart GUS' pounds 1.9bn hostile bid for the group.
City observers believe the outcome of the deal remains on a knife edge, although Mr Rose faces a difficult task persuading shareholders to ignore the cash offer.
The acquisition of Metromail will make GUS one of the largest providers of tailor-made marketing information in the US and further its ambition to become a global force in the industry.
Metromail specialises in providing lists for retailers and phone companies which can be used to target customers. It attempts to identify those people who are most likely to buy its clients' products.
For example, some of its main customers are nappy makers who pay Metromail for lists of expectant mothers. However, along with rivals it has been blamed for adding to the amount of junk mail put through people's letter boxes every day.
Metromail's sales have doubled to $329m (pounds 197m) since 1993 and the group employs 3,200 people. GUS will merge Metromail's databases with those of Experian, its existing marketing information group, which serves mainly financial services groups.
Experian specialises in identifying different social groupings from post codes and providing credit checks for banks and financial institutions.