American Job Builders Tax Reform Act of 2011 - Amends the Internal Revenue Code to: (1) increase from $10 million to $40 million the gross receipts threshold for determining whether a small contractor may adopt an accounting method for reporting income from a construction contract other than the percentage of completion method; (2) allow an annual inflation adjustment to such increased $40 million threshold amount, beginning after 2011; and (3) exempt construction contracts from alternative minimum tax rules for reporting income from long-term contracts under the percentage of completion accounting method.