After the first steps in the UK and France (with a 50% surcharge on bonuses payable by the banks, which they seem to have largely decided to absorb), the US government has now decided to impose a tax on large banks:
To recover taxpayer losses from the federal government's bailout of the U.S. economy, President Barack Obama plans Thursday to propose taxing large banks and other companies based on their exposure to risk, White House officials said. (...)
Under the proposal, a 15% tax would be levied on liabilities. The tax would apply to bank holding companies, thrifts, insurance companies that own financial arms and broker dealers with at least $50 billion in assets that received assistance under TARP, the FDIC's temporary loan program or other crisis efforts. (...) Under that formulation, banks that lean heavily on funding sources other than customer deposits would pay proportionally higher taxes. That means that Goldman Sachs and Morgan Stanley could get penalized.
As described, this looks like a pretty smart tax, linked to the size of banks' balance sheets and thus providing a counter-incentive to the banks' tendency to grow (and become too-big-too-fail). It encourages them to build up higher quality assets like deposits (rather than relying on wholesale markets too much - such reliance was one of the root causes of the crash).
Another smart feature is that the amount to be recovered would depend on the actual cost of the most recent bailout - thus it may last longer if the bailout ends up being bigger (and hopefully it will be made permanent, to build up funds for future crises and maintain the right incentives).
On the flip side, it may encourage banks to further sell financial assets to third parties in order not to carry them on their balance sheet. This was also at the root of the crisis (all the "securitization" business was about creating tradeable securities out of run-of-the-mill bank assets, so as to free up capital and do more business) as it created a distance between those that deal with the borrowers and those that hold the debt. Can one believe that investors have learnt the lesson of the past crisis about buying various kinds of papers from banks without properly analysing them? One can dream, but something probably needs to be done about this.
As a general point, it's at least a tax on the financial industry, and thus a step in the right direction, by creating some pressure towards downsizing and making it give back some of its loot to the real economy, via the government.
The British bonus tax exemple suggests that bonuses have not been reduced, and banks have borne the cost of that tax, passing it on to shareholders. But in the face of sustained efforts by governments (not the case right now as the UK tax is a one-shot this year), managers are not going to be able to keep on squeezing shareholders (who will get militant or simply sell) and may eventually end up cutting bonuses.
At some point, government will realise that the simple solution is to increase marginal taxes on high incomes; if done in a coordinated way between the US and Europe, the bankers and traders and hedgies will have little choice bu to pay up. To move to other jurisdictions not to pay taxes, they will have to abandon their homes, friends, schools and the life in NY, London or Paris; and if they do, maybe it's not a bad thing after all given that their activity has proven to be such a drain on society. The tax havens are welcome to them.