Whether a Tobin Tax would affect volatility in the same way as underlying market transaction costs is not clear.

FORBES: The Stupidity of the Robin Hood Tax Reaches America

Opposition to a financial transaction tax says the extra cost would undermine liquidity, adversely affect market quality and distort the value of a security.

FORBES: Risk Of Going Hungary With A Financial Transaction Tax

We are blocking this transaction because the proposed merger would substantially lessen competition in the tax preparation software market, resulting in higher prices, lower quality and reduced innovation.

FORBES: Antitrust Suit Filed Against Top Tax Preparer H&R Block