A decline in the stock market might also, for example, reduce confidence in the US economy and reduce the willingness of foreigners to accumulate the increment in US liabilities associated with the current account deficit. And the net effect will also depend on the policy response to the adverse effects of the unwinding of any imbalances.
For example, it would be difficult to determine whether mobile banking is purely supply driven (in terms of enhancing the capacity of the chip in the mobile to undertake banking functions as well) or is it demand driven by the customers who would see this particular service as a “value added service”, (along with ringtone downloads for example) that has prompted banks, payment service providers and telcos to provide this service.