[1] The policy, rather than formal regulation, first articulated in 1990, reflects the competitive concerns of more concentration as well as the broad political unpopularity of further bank mergers.
"[12] Wallis recommended that the "Four Pillars" model be dismantled, to leave the banks subject to the same merger competition tests as other businesses.
In response, the then Coalition Treasurer Peter Costello's removed the pillar status of the two insurers (National Mutual had by that time already been acquired by AXA), but the ban on mergers of the remaining four banks was retained, with the rider that none of them were considered immune from foreign takeover.
[13] In 2017, Peter Costello said that the advantage of having big banks under the four pillars policy was stability, which he attributed to Australia faring well during the 2007–2008 financial crisis.
[9] The policy has been criticised for being anti-competitive by ensuring that the four major banks are immune from takeover by the most likely suitors.