Despite all that's gone down over the last few years, I'm an enthusiast of "financial innovation". I think it essential that we remake our financial system into something so different from what it has been that we would hardly recognize it. Doing so will require a lot of innovation.

But there's no question that the current financial crisis was abetted and largely enabled by many of the "innovations" that became ubiquitous in the financial sector earlier this decade — CDOs, SIVs, (arguably) CDSs, etc. To square the circle, I resorted to an old cop-out: the revolution hasn't been tried. There's good innovation and there's bad innovation. The stuff that didn't work was the bad stuff. Lame as that may be, it is what I think, and I did try to put some flesh on how we could distinguish good from bad going forward. Then Dani Rodrik came back with some fair questions:

OK, now that we have collectively gotten over our finance fetishism, and are willing to accept that some innovations can be bad, what does this mean for regulatory and supervisory approaches?

For example, it is one thing to say that good innovations are those that are transparent, and another to figure out how policy sorts out the degree of transparency of innovations and how policy makers treat innovations of different kinds. Does this line of thinking imply that some degree of paternalism in regulation is unavoidable ("no, you cannot issue this particular complicated derivative!")

I think we need to discriminate here between the structural and substantive terms of financial instruments. A contract is "structurally" transparent if, conditional on any set of observable real economic outcomes, it is clear what cash flows are compelled of all parties. A contract is "substantively" transparent if the economic outcomes that determine the cash flows are themselves susceptible to analysis. A mortgage-backed security, for example, might be structurally transparent but substantively opaque: Knowing the performance of the bundled mortgages, it might be easy to calculate the cash flows payable to all tranches. But as a practical matter, it might be impossible to estimate the performance of a thousands of heterogeneous loans in a volatile housing market. Common stock is arguably both structurally and substantively opaque: Even if one knows with certainty the long-term performance of a firm, the cash flows due a stockholder can be difficult to predict. And the future performance of a firm is itself very hard to estimate.

I think a strong case can be made for regulatory promotion of structural transparency. Contracts can be made arbitrarily complex, and there is little reason to think that skill at crafting and understanding challenging legal documents overlaps with peoples' ability to evaluate economic risks and outcomes. It would be useful to have standardized contracts so that those not expert in the law of finance can participate in financial markets without fear of getting screwed because their lawyers missed something. Also, I think regulators have a legitimate interest in ensuring that investors do not accept contingent liabilities foreseeably beyond their capacity to pay. To do so, regulators must be able to estimate the liabilities that counterparties could be called upon to bear. The potential extent of those liabilities should be evaluable without a lot of analysis or guesswork.

That said, I don't think the best approach would be to forbid nonstandard contracts. Instead, regulators could "bless" certain contractual forms as well-defined, while creating penalties for those who offer contracts that are structurally opaque or that serve to hide embedded leverage. Parties who have good reason to deviate from very standard contracts would have the ability to do so, but would risk of being punished if those instruments are deemed to have violated standards of clarity. In other words, instead of eliminating "bad" contracts, regulators should take on the role of organizations like ISDA and proactively define "good" contracts that meet needs they identify by monitoring "exotics" that gain prominence in the market. Unlike ISDA, however, regulators' primary mandate would be to ensure that the contracts they bless are well thought out from the public's perspective: that "catastrophic success" of those contracts would not create fragile networks of counterparties or other hazards. "Blessed" contracts might well include obligations to periodically report contract valuations notional and net, and collateralization to a public registrar. They would rely upon collateral much more than counterparty for security (to restrict embedded leverage), and provide for standardized means of termination or novation, to prevent the emergence of economically useless but systemically hazardous multilaterally offset positions. They might work proactively to encourage the formation of centrally cleared exchanges, to permit counterparty neutrality with less collateral or risk of early termination, as new forms of contract grow popular.

The case for regulatory promotion of substantive transparency is much weaker. Economic problems that appear inscrutable to distant regulators might in fact be quite tractable to those "in the know". (Pace Arnold Kling and Richard Serlin, it's important to point out that when I take "transparency" as desirable, I am not suggesting that people should be compelled to reveal hard-won information without compensation. People who can predict economic outcomes should be paid for doing so. But contracts should generally be structured so that the relationship between economic outcomes and contract cash flows is clear. How much "inefficiency" is desirable, meaning how slowly contract prices should respond to information revelation, creating opportunities for the informed to profit, is a complicated question. We need to balance the interests of uninformed investors, whose capital may be required for large projects, and information workers, who need incentives to evaluate competing projects.)

Suppose a group of people learned that, in the near future, there would be an incredible economic need for COBOL programmers, and looked for a way to monetize this. Noting that former COBOL programmers are much more creditworthy than their FICOs suggest, they might wish to buy up the loans of this dispersed, obscure population. Knowledgeable individuals would not want to buy up individual loans: instead they would want diversified exposure to the pool of COBOL programmer loans, since individual circumstances vary widely. Our cabal only knows that on average COBOL programmer loans are underpriced.

So, our insiders should hire up some financial engineers, and construct an asset-backed security containing a pool of consumer loans to COBOL geeks. They could each take diversified shares of the pool, with some assurance of having bought undervalued assets. Once the ABS is established and divvied up, they would have every incentive to reveal their information, explain to the world why COBOL is the next big thing (and how their ABS was structured), and sell to the world at fair-ish value for a quick profit.

This chain of events is informationally idyllic: Knowledgable people are compensated for revealing hard-won information, and economic assets become more accurately priced, which should feed forward into better decision-making. But if regulators are empowered to evaluate the "substantive transparency" of investment contracts, they would certainly have nixed an ABS made up of loans to an eclectically selected population of individuals without justification. Up-front revelation of the justification to regulators, however, might leak and allow a larger player to buy up the whole pool, eliminating the opportunity.

Also, consider common stocks. No rational regulator concerned with substantive transparency would approve of common stock, if it were a novel investment vehicle. It guarantees no cashflows whatever, its "control rights" are so weak for most purchasers that representations thereof should be viewed as fraudulent. Empirically common stock behavior is very weakly coupled to the performance and health of the firms that stocks fund. The only instrument in wide use more substantatively opaque than common stock is fiat money.

I think common stock is a deeply imperfect instrument, one that we should work to improve upon and eventually replace. But, there's little question that over the several hundred years between the invention of joint stock companies and the advent of information-technology that might make more fine-grained claims practicable, common stock served a useful purpose, both in terms of pooling capital and risk, and promoting information discovery and revelation.

Still, much of our current catastrophe was caused by investors investing overeagerly in securities whose structures were clear enough, but the economic substance of which they were entirely incapable of evaluating. Rather than banning such securities, we should turn our attention to understanding why they did this. A lot of very opaque securities (both substantively and structurally) were invented, sure. But how did they vault from idiosyncratic experimentation to widespread implementation? This had to do with the structure of financial intermediation, and it is there that I believe that regulatory energy should be focused, rather than on evaluating the terms of contracts.

Flawed financial instruments only become policy issues when people responsible for investment on a significant scale decide that what they don't know won't hurt them. This can happen by virtue of fads and fashion, the madness of crowds: consider internet stocks, or blind faith in diversification and "stocks for the long run". But most poor investment, in dollar-weighted terms, is not taken by foolish individuals placing their own money. Bankers and institutional investors are on the one hand granted the power to control investment on a very large scale, and on the other hand make consistently awful choices. Delegated money, rather than trading off return and safety, often trades return for safe-harbor. Absurd contracts that appear to offer high returns are very attractive to money managers of all stripes, if they offer a veneer of safety and "prudence", or better yet, if they become conventional.

Getting regulators in the habit of banning some classes of contracts (or worse, requiring them to approve novel contracts) would have the perverse effect of certifying the instruments that are permitted. A better approach would be to eliminate safe-harbor for intermediaries by insisting that they be substantially invested in the funds they manage, and on the hook — financially, not just reputationally — for losses as well as gains. (Obviously, we should eliminate safe-harbor that derives from rating agency certifications or statistical risk models. But that won't be sufficient — professionals will always manufacture "best practices" and find safety in numbers, or hide behind consultations with experts and representations by prestigious sources.)

Fundamentally, the agency problems associated with financial intermediation are deep, and it will take a lot of reform — and innovation — to find good solutions. Regulation to promote structural clarity in investment contracts and manage leverage and counterparty risk may help limit the damage, but won't be nearly enough. I think we need a fairly wholesale restructuring of financial intermediation, one that limits the scale and leverage of intermediaries, segregates transactional balances and noninformational savings from informational risk investment, and ensures that those who do manage large quantities of wealth land in penury or in prison before the taxpayers are on the hook to make private losses whole. But having regulators review and restrict the substantive terms of financial contracts strikes me as a bad idea.