TAX GAP Act of 2010

Taxpayer Advocacy and Government Accountability Promotion Act of 2010 or the TAX GAP Act of 2010 - Amends the Internal Revenue Code to: (1) extend requirements for the reporting of payments to governmental units; (2) require information reporting of rental income from real estate; (3) require additional information on tax returns relating to mortgage interest; (4) expand information reporting requirements for bank accounts, non-interest bearing deposits, and electronic filings by paid tax preparers; (5) impose a continuous levy on federal contractors for tax liabilities and on payments made to Medicaid providers or suppliers; and (6) increase penalties for failure to file correct information returns, failure to file correct payee statements, and for intentional disregard of information reporting requirements.

Directs the Secretary of the Treasury to: (1) revise Schedule C of tax form 1040 (self-employment income) to require reporting of additional gross receipts and expense information by sole proprietors; and (2) report to Congress on efforts to improve voluntary compliance by sole proprietors.

Authorizes the Secretary to make an apology payment to a taxpayer for any action or inaction by the Internal Revenue Service (IRS) that has caused the taxpayer excess expense or undue burden. Excludes the amount of any such apology payment from taxpayer gross income.

Requires the Secretary to submit to Congress: (1) a study of whether the IRS has sufficient capacity to incorporate expanded information reporting requirements; (2) a report on taxpayer assistance and tax simplification; (3) a study to quantify the effect of tax penalties; (4) comprehensive and detailed reports on a strategy for reducing the tax gap; (5) a study on revenue increases and costs with respect to tax gap legislation; and (6) reports on worker misclassification (e.g., employees classified as independent contractors).