Economist Paul Krugman sees value in proposals coming out of the UK to tax financial transactions to discourage speculators, in part because it would discourage overnight financing on the repo market.
From his November 27 column:
It’s true that a transactions tax wouldn’t have stopped lenders from making bad loans, or gullible investors from buying toxic waste backed by those loans.
But bad investments aren’t the whole story of the crisis. What turned those bad investments into catastrophe was the financial system’s excessive reliance on short-term money.
As Gary Gorton and Andrew Metrick of Yale have shown, by 2007 the United States banking system had become crucially dependent on “repo” transactions, in which financial institutions sell assets to investors while promising to buy them back after a short period — often a single day. Losses in subprime and other assets triggered a banking crisis because they undermined this system — there was a “run on repo.”
And a financial transactions tax, by discouraging reliance on ultra-short-run financing, would have made such a run much less likely. So contrary to what the skeptics say, such a tax would have helped prevent the current crisis — and could help us avoid a future replay.