Excel Viewer Adobe® Reader Featured articles Effects of Forms 1040-X and 1120-X Post-filing Adjustments on SOI Estimates PDF by Derrick Dennis, Jennifer Ferris, Gloria Gagin, Tuba Ozer-Gurbuz, Julia Shiller, and Christopher Williams This study sought to measure the impact that amendments would have on SOI tax return statistics. Based on the results, there is an important observation about SOI estimates that can be made for individual and corporate income returns. In this preliminary study looking at 2013, some 2.3 percent of individual income tax returns (Forms 1040) and 0.52 percent of corporate income tax returns (Forms 1120) were amended (using Forms 1040-X and 1120-X). These amendments decreased the estimated total tax from individual filers by only $2.1 billion (0.16 percent) and decreased the estimated total tax from corporate filers even less, by $87.8 million (0.03 percent). Thus, the study’s review of individual and corporate tax returns from 2013 suggests that while SOI tax return statistics would be affected by post-filing adjustments, current SOI statistics do not significantly change. Related Link: Individual Income Tax Return (Form 1040) Statistics Departments SOI Sampling Methodology and Data Limitations Upcoming SOI Data Releases Historical Tables and Appendix