Acromas had earlier announced that it intended to sell a minimum of 77m shares in specialist insurance group Saga, representing a seven per cent stake in the company.
The shares are being offered to individual investors through an accelerated bookbuild.
Bank of America Merrill Lynch (BAML) is acting as bookrunner on the deal, with Numis acting as lead manager.
Acromas said it had agreed not to offer, sell or otherwise transfer shares in Saga for a period of 90 days following completion of the placing without the consent of BAML.
Acromas is owned and controlled by funds managed or advised by Charterhouse Capital Partners, CVC Capital Partners and Permira.
It was created in 2007 as a parent company for over-50s insurer Saga and AA.
Shares in Saga, which made a disappointing entry to the public market last May, closed down by 0.15 per cent yesterday.