ANZ and NAB were "keen to merge" in June 2008, writes the former treasurer, Wayne Swan, in his book 'The Good Fight'.
Swan writes that such a merger "would have left us with just three banks … I was never going to be turning for this."
Swan scans many, but not enough, details of the unfolding crisis in his account of his recent political career, serving as treasurer in a two-term Labor government.
Swan appears to have deliberately kept the bank deposit guarantee in his back pocket as the financial crisis unfolded six years ago - before ultimately introducing it in the nick of time.
The background talks between Swan, Treasury, APRA and RBA sadly do not rate much of a mention in the book. So if there was explicit advice on bank runs, this is downplayed.
He writes that "the pattern had begun to emerge of people taking their money out of smaller financial institutions, and, in some cases, out of the financial system altogether."
In the hours before announcing the guarantee one October afternoon "Armaguard experienced its busiest weekend on record."
Swan writes that Australia's financial regulators made it clear to banks that "higher risk lending would mean higher capital requirements."
"Some of our lenders wanted to dabble in the types of risky sub-prime lending we saw in the US," Swan writes. He does not say who but CBA and Westpac had, and still have, an involvement with no-conforming financing.