Quote from benwm: I think we're winning this battle...
A member of the academic community (judging by his 'ibidem') has recently contributed to the IMF a comprehensive list of arguments against transaction taxes (I do admit to one count of reciprocity manipulation - as in bribing + toadying - to entice one high-profile scholar to do it, so I hope it was actually you Ben

. Anyway, this mini-treatise is so comprehensive and well-referenced (i.e. ready to use by source-checking journalists or report writers), that it is well worth saving it for our ongoing battle with the latent Tobin virus...
FINANCIAL TRANSACTION TAX WOULD BE DISASTROUS (1 of 2)
Tax rate of 0.005% is only "nominal" to those who are ignorant of how markets work and who do not understand the difference between profit and margin. The margins which allow marketmakers and market specialists (short term and long term speculators) to create liquidity, lower costs and increase access to capital, are razor-thin
By way of example, the cost of trading EURUSD is typically 1 pip (0.001%) or 2 pips (0.002%). For many traders, the cost (ie the spread) is the difference between profitability and non-profitability, ie the difference between contributing to liquidity on the one hand by participating in the market, and economic inactivity on the other. A proposed FTT of 0.005% would impose between a 250% and 500% increase in costs!!! This would absolutely decimate affected markets; it would have a plurality of highly undesirable effects. As Otmar Gissing, former European Central Bank chief economist, stated on 26th October 2009, "[The FTT] is not well founded and would fail"
1. Liquidity
The FTT would destroy volumes and greatly discourage hedging; "The Tobin tax would discourage hedging...[which] helps to spread risk more evenly" Helmut Reisein, OECD Development Centre, May 2002; "A transaction tax...I think would have very, very negative implications for volumes and for the cost of trading for retail investors" Duncan Niederauer, CEO NYSE Euronext, January 2010
2. Volatility
(a) AFA 2003 Washington DC Meetings, EFA 2002 Berlin Meetings; Presented Paper - studies have repeatedly shown that transaction taxes INCREASE voltatility; they deter the continual realignment of price to market conditions and reduce the diversity of participants in the market;
http://papers.ssrn.com/sol3/papers.cfm?abstract_id=311700
(b) Lanne,Markku and Vesala,Timo (2006): "The Effect of a Transaction Tax on Exchange Rate Volatility,/"/ Bank of Finland Research Discussion Paper No. 11/2006
http://papers.ssrn.com/sol3/papers.cfm?abstract_id=1018363 "A Tobin tax will lower market liquidity and hence raise volatility. In other words, it can prove more damaging than the exchange rate stability it is aimed at curing" Ganesh Raj, Tax Partner, National Leader, Ernst & Young, India, Business Standard, 11th November 2009
3. Jobs
Overnight, an 0.005% FTT would destroy or jeopardise hundreds of thousands of jobs and businesses, as well as indirect employment and significant tax receipts. For the intraday specialist who provides liquidity, smooths volatility, continually adjusts price to market conditions, pays taxes and provides jobs, an 0.005% FTT might typically be tantamount to a new 50% tax on profits in advance of and in addition to general taxation, as well as a 50% tax on losses
"...the [FTT] thesis rests on an assumption that speculators - whether in forex or any other market place - are a bad breed. In fact they are an exceptionally useful lot, working day-in, day-out, risking their own wealth to supply a thing called liquidity" The Guardian, 30th August 2001 . What might one expect if governments began taxing general business income and capital losses at 50%?! Immediate retardation in economic activity would be inevitable; and the effect on the market would be no different.
"The effect of a transaction tax can be extremely damaging...Essentially it's a tax on jobs" Xavier Rolet, Chief Executive of the London Stock Exchange
4. Total lack of efficacy
"While the illiquid and low trading frequency credit markets (at the heart of the recent trouble) froze last year, the more liquid equity markets had fewer issues clearing and the highly liquid, rapidly trading Group of Seven government bond and forex markets cleared consistently. So the tax would hit the source of the problem the least and directly diminish the liquidity, therefore increasing the risk, in the markets that did continue to function because these markets have a higher average trading turnover" David Beddington, Letters Page, Financial Times, 15th December 2009 - intraday market specialists bore no responsibility for the credit crunch and received no government money. Had the credit derivatives which caused the credit crunch been subject to rigorous and continual pricing in the market, the credit crunch would not have happened. The guilty parties were a number of readily identifiable large institutions. An FTT would sanction the cure, not the problem!
"The solution is clear, and it is not a tax on financial transactions; bring default risk back into the calculations of unsecured creditors and other counterparties of the financial sector. This would eliminate the capital subsidy to the industry. The obvious way to do this is through the creation of a "special resolution regime" as an alternative to bankruptcy for all systemically important financial institutions" Willem Buiter, Financial Times, 2nd September 2009
5. Increased costs
"The [FTT] would merely pass on that cost to the borrower" Henry Kaufman, Author of The Road to Financial Reformation, Bloomberg Radio & Television, 2nd September 2009 - the cost of the FTT would be passed on to the saver, the investor and the pensioner. The cost increase would be a double whammy - the tax itself plus in addition wider spreads caused by the destruction of liquidity;
"Transaction taxes carry the risk that...it is the ordinary saver who ends up paying" Richard Saunders, CEO Investment Management Association
6. Systemic instability
"In reality, the short-term capital movements that are blamed for market volatility often serve to keep markets functioning and stable. That's the historic role of the 'market specialist', whose socially critical function would be attacked by a Tobin-style tax on short term trades" The Tobin Tax: A Bad Idea Whose Time Has Passed, IRRP, A.R. Riggs and Tom Velk
7. (political)