So now the hard work really begins. The SEC's decision today to require registrants (ie: companies with listed securities) to start filing their financial statements in XBRL format is pretty similar to the proposed rule announced in the middle of the year. As widely expected, there is a slip in the timing. It will start for company filings (quarterly or annual) as from 15 June 2009, ie: 2009-Q2 10Qs instead of the larger and harder 2008-Q4 10Ks as originally anticipated. They've also pushed back the timing for the roughly 8,000 mutual fund risk/return summaries to 1 January 2011, instead of the middle of 2009.

The Commission is not unanimous on the liability arrangements. Commissioner Aguilar is voting against the entire proposal because he wants the liability and the assurance arrangements contained in the proposals greatly strengthened.

For what it's worth, I think that the liability carve-out arrangements are an attempt to ease the transition costs - the change management involved in a complex new technology - and the SEC (particularly the Chairman) are relying on new SEC leadership to reinstate them. We need to wait for the final rule to see the details, but there appears to be a phase-in arrangement for liability (and therefore assurance) in any event. This should be a relief for a lot of auditors.

Commissioner Aguilar is pointing out that the current economic climate is the exact moment at which the regulator could simply reject the need for a carve-out. Since the requirements for audited financial statements in ASCII or HTML are not going away, and the liability and assurance arrangements for them remain, I suspect the issue is almost moot.

However, I think, from an accuracy and consistency perspective, we should be looking for XBRL filings to be in iXBRL (embedded inside web pages) format. This should happen very quickly and at that point, the liability arrangements must be uniform. Cox seems to have made this point, right at the end of the meeting.

A number of the other details will be in the rule. Final SEC rules tend to be published a week or so after these open meetings. Stay tuned.

I think this decision today is much bigger than most people realise. Thanks and congratulations to the SEC, particularly Paul Wilkinson, Jeff Naumann, David Blaszkowsky and (more recently) Walter Hamscher, all those involved in the US GAAP XBRL taxonomy project at XBRL US under Mark Bolgiano and Campbell Pryde, as well as the extraordinary international collaboration that XBRL continues to represent, especially at XBRL International.