Graeme Samuel, chair of the Australian Competition and Consumer Commission, warned banks over signalling their interest rate pricing plans to each other on Friday, saying it borders on misconduct.Speaking on Adelaide radio, Samuel said that he worried that too many of the banks were signalling to one another - and "the world at large" - that they planned to lift their rates. The Australian reported Samuel's comments on Saturday."That sort of price signalling that worries me a bit, because what it's really doing is saying to their competitors, 'Hey guys, if you lift your rates, we're going to lift them too, so you don't have to worry about it,'" Samuel said."And that sort of price signalling really borders on areas that in the US and Europe are potentially, you know, misconduct."Efforts by the banks to coordinate action on home loan pricing over the last two months, if that's what they were seeking to do, has proven haphazard.The last bank profit reporting season opened with a comment by the managing director of Bendigo and Adelaide Bank, Mike Hirst, who said his bank was a price taker and that "the issue of whether there will be a rise in rates one way or another lies in the hands of the majors."Meanwhile, Commonwealth Bank has left rivals, investors and customers confused as to its intentions, as a lot of investor belief that banks may lift home loan margins once again stems from briefings in the weeks following its full-year profit announcement.More recent speeches by bank executives about elevated funding costs (including the CEOs of ANZ, Commonwealth and Westpac) have covered well known ground but failed to provide the impetus for any one bank to take a pricing lead.These three banks are also constrained by National Australia Bank's position on home loan pricing, which appears to be wearing lower margins in the interests of reviving the bank's retail banking business.