KNOC said on Friday that it had bought 27.3m. Dana shares at 1,800 pence each, the price of its declared final offer.
A spokesman for KNOC declined to comment on the identity of the stake sellers or whether they were shareholders who had already indicated that they would accept.
However, Schroders – one of the shareholders who stands in line to accept the offer – issued a statement to say it had disposed of 10.6 million shares on Friday.
In August, KNOC said it had secured non-binding letters of intent to accept the £1.67bn from around 49 percent of shareholders.
It requires 75 per cent acceptances to delist Dana, with the first deadline for acceptances of the offer this Thursday, 23 September.
Analysts believe the bid is likely to succeed as KNOC has refused to budge on price and no new bidder has emerged.