Almost 20% of TDs who voted for the government's bank guarantee scheme, including Fine Gael TD Richard Bruton, recently held shares in Irish banks, according to the last Dáil register of members' interests.
The guarantee was supported by all the political parties apart from the Labour Party, handing the government an overwhelming majority.
In all, just one TD who owns bank shares, Labour's Willie Penrose, voted against the plan.
Between Monday's stock market crash and the guarantee becoming law on Thursday, Irish bank shares rose by an average of 65%, with Anglo Irish Bank shares more than doubling in value. Anyone owning these shares stood to make a large paper gain on the week, although even this rise failed to offset steep declines from earlier this year.
It is impossible to assess the individual gains as TDs are not required to disclose the size of their shareholdings, with prominent figures such as Fianna Fáil's Seán Haughey and Micheál Kitt, the Green Party's Mary White and Fine Gael's Alan Shatter and Michael Noonan declining to provide this information.
Just three TDs – Fine Gael's James Reilly and John Perry and Fianna Fáil's Michael Kennedy, disclosed the size of their modest bank holdings, all of which are worth under €10,000 even after this week's rally.
Irish politicians have been investing in bank shares for a long time.
There are also long-standing links between banks and Fianna Fáil.
The chief executive of the Irish Bankers' Federation, Pat Farrell, is a former general secretary of Fianna Fáil.
Fianna Fáil is also well known for its connections to property developers, who may end up being beneficiaries of last week's intervention.
This newspaper revealed in April that there was a record number of donations from property developers to Fianna Fáil TDs last year, with corporate donors including Glenkerrin Homes, PJ Walls and Ascon.