Clearly, my clients aren’t the only ones asking. In a recent report (PDF file), the Government Accountability Office (GAO) stated that about 38% of the taxpayers reporting stock sales on their 2001 returns incorrectly reported their gain or loss on the sale. Roughly two-thirds of taxpayers underreported capital gains in securities sales, while roughly one-third overreported, according to the GAO. The report comes amid Internal Revenue Service estimates that taxpayers’ errors in calculating capital gains and losses — or just plain cheating — led to a $17 billion gap in the collection of taxes due. The IRS has said the total tax gap is $290 billion, primarily from small businesses and independent contractors whose taxes aren’t withheld from their paychecks. Sen. Evan Bayh (D-Ind.) introduced the START (Simplification Through Additional Reporting Tax) Act in March of this year. The START Act would require brokerage houses and mutual fund companies to track and report to both taxpayers a