Auction Technology tumbled on Thursday after TA Associates and ECI Partners sold around 12.6m shares in the company in a placing.
The shares were sold to institutional investors by way of an accelerated bookbuild at a price of 1,500p each, raising around £189m.
Following completion of the placing, TA Associates will hold approximately 21.4m shares in ATG, or a stake of 17.9%. ECI Partners will hold around 6.5m shares, which is a 5.4% interest.
JPMorgan and Numis acted as joint global coordinators and joint bookrunners in connection with the placing.
At 1215 BST, ATG shares were down 13% at 1,427.99p.
