Crystal Amber, the activist investor firm that held a stake in Aer Lingus and had put pressure on IAG to pay a higher price as part of its takeover bid, made an £8.7m (€12m) profit from selling its shares in the airline.
The investment firm revealed the profit yesterday. Crystal Amber only acquired its 2.8pc Aer Lingus stake in summer last year. It was the single biggest institutional shareholder in the airline.
It's believed that Crystal Amber established its position in Aer Lingus after buying some shares sold by businessman Denis O'Brien.
Crystal Amber, which is headquartered in Guernsey but whose operations are in London, is run by Richard Bernstein, a former Schroders analyst.
Immediately after acquiring its Aer Lingus stake last year, Crystal Amber weighed in to the debate about the future of Aer Lingus pensions.
The airline agreed to stump up almost €200m to help establish a new defined contribution scheme for its workers to replace the defined benefit Irish Airlines Superannuation Scheme.
Mr Bernstein said at the time that the €191m Aer Lingus had agreed to pay was the "absolute limit" that the airline's shareholders should be paying. The resolution of that pension dilemma was a key motivating factor for IAG in launching its takeover bid for Aer Lingus last December.
When IAG launched its indicative offer for Aer Lingus, the airline group said that it was willing to pay €2.30 per share.
Mr Bernstein described that offer as "opportunistic" and said IAG would have to do better.
He said that Crystal Amber would consider a fresh offer if IAG returned with one.
At the time, Davy Stockbrokers suggested that €2.50 per share would be a possibility.
IAG later revised its bid to €2.40 per share, and eventually to €2.50 a share, with an additional five cent per share dividend being paid by Aer Lingus.
Other shareholders in Aer Lingus included the State, with 25.1pc; Ryanair with 29.8pc; and Etihad with 4.9pc.
The takeover of Aer Lingus is now effectively completed, with the shares expected to delist from the stock exchange next week.
The sale of its Aer Lingus stake, and of a 19pc holding in chocolatier Thorntons, helped Crystal Amber increase its net asset value by 4.6pc during the 12 months to the end of June. It sold its Aer Lingus stake once the State said it would sell to IAG.