Contemporary IAS and its successor IFRS are old GAAP. The APB and ARB kind. That was my feeling when I began to practice with it as managing director of finance for a US sub of a European reporting parent (LSE; NYSE listed). The more I interpreted and applied it, with oversight by the European audit firms, the more it looked, walked and quacked like “old” US GAAP.

IAS’s language was familiar. It felt like it could have been lifted right out of the APB canon. The successor IFRS releases utilize modern rulemaking’s tools, while keeping IAS’s “go light” frame. Both ideas are a step in the right direction.

US GAAP has gamely tried to keep up with the viral development of financial instruments, tax strategies and hybrid ownership instruments of the last three decades but it has always used a retrospective lens. Rulemaking architectures like GAAP address historic practices and do so narrowly, for the sake of reshaping prevalent undesired outcomes into ones closer to the “fairly presents” format.

But GAAP has always played catch up with the kinds of transactions and business that have developed serially since the 80’s. By the time it has gone through its process of identifying issues, drafting rules, issuing the final rule, amending and then addressing situation specific elements of the rule with FSP’s or EITF’s, the marketplace has issued another wave of its own mutations and business has stampeded into the related practice.

With a true principals based rule framework, there would be far less chasing the marketplace’s machinations through issuing an avalanche of caveats and special circumstance interps. The weight would fall to interpretation of the larger principle. And there’s the rub for any convergence between US GAAP and IFRS. Who has jurisdiction over review and enforcement of interpretation and application?