Why was a blanket bank guarantee the preferred option?
One key question remains after the latest evidence at the Banking Inquiry - why was a blanket bank guarantee given on that fateful night?
Not that we learned much new about the collapse of the banking sector and the subsequent €64bn bailout after hearing from ex-AIB chief executives Eugene Sheehy and Michael Buckley and outgoing boss David Duffy.
The best nuggets again focused on the night of the bank guarantee and how nearly everyone there, bar Government representatives, was frozen out of the final talks on that fateful night of September 29, 2008. One key question has emerged, though.
If nearly everyone in Government buildings involved in the talks leading up to that €440bn decision wanted a four-bank guarantee that excluded Anglo Irish Bank and Irish Nationwide, then how did we end up with a blanket one?
Mr Sheehy told the inquiry that former Finance Minister Brian Lenihan wanted AIB to take over Anglo, ahead of the bailout, although the bank refused point blank.
He also told the inquiry that AIB executives had proposed a four-bank guarantee on the night, focusing on deposits at the bank, in a move that would have set Anglo and Nationwide loose.
And it is this proposal that bankers giving evidence, so far, claim was their preferred option. Of course, a so-called lesser guarantee would also have had repercussions, given the disastrous international climate - Lehman Brothers filed for bankruptcy just weeks earlier.
But it now seems it will be down to politicians and civil servants to explain why the costly blanket guarantee option was the one settled on.
Step up former Taoiseach Brian Cowen.
Mr Cowen has already disputed the evidence of Central Bank Governor Patrick Honohan that he had "overruled" Mr Lenihan, who wanted to nationalise both Anglo and Nationwide.
He also denied that he had dismissed plans by Mr Lenihan not to include subordinated or junior bank debt in the guarantee.
It is understood Mr Cowen will give evidence in July, but a number of other contributors, including key officials at the Department of Finance, could also throw more light on the subject.
It could well be standing room only later this summer.