The chairman of AstraZeneca and John Varley, the former chief executive of Barclays who sits on its non-executive board, both bought shares in their drug company just a month after Pfizer first approached it with a takeover bid.
Mr Varley bought £156,000 of AstraZeneca shares on 7 February, while Leif Johansson spent £19,000 five days later. The share price subsequently leapt as the US drug giant returned with an offer proposal, meaning that the shares bought by Mr Varley are now worth £40,000 more.
Pfizer's chief executive, Ian Read, first approached AstraZeneca with a takeover proposal on 5 January but Mr Johansson and other key top brass rejected it.
AstraZeneca said: "After a preliminary approach in January, which was rejected by AstraZeneca, Pfizer informed the company that they were no longer actively considering making an offer. That was the end of the matter.
"Any subsequent share purchase by a board member reflects confidence in the management team and the prospects of the company as an independent business."
Less fortunate among directors trading at the time was the chief medical officer Briggs Morrison, who sold £437,000 of shares on 31 March. Had he held on to them, they would have been worth nearly £110,000 more today.
The news of the directors' dealings came after The Independent disclosed that Pfizer's Mr Read and his top scientist sold more than $12m (£7m) of their Pfizer shares just weeks before launching their bid.
The Swedish government yesterday repeated its condemnation of Pfizer's approach for Anglo-Swedish AstraZeneca. It held a press conference to say why it had taken the "extremely rare" action of becoming involved in a private deal, citing fears for the entire European research and development base. Pfizer's reputation in the country was scarred by job cuts it imposed after buying Pharmacia.
The deputy prime minister, Jan Bjorklund, said his government had held "several" conversations with British ministers, including Nick Clegg and Vince Cable, warning of their experience with Pfizer.