Self-Initiation Trade Enforcement Act of 2021 This bill establishes within the Department of Commerce a task force to identify and recommend actions related to potential countervailable subsidies, dumping, and circumvention. Dumping and countervailable subsidies are unfair trade practices that cause (or threaten to cause) material injury to U.S. industries by importing products (1) that are similar to those sold in the U.S market at less than fair value (dumping), or (2) with the assistance of subsidies from a foreign government or public entity (countervailable duties). Specifically, the task force shall identify (1) potential countervailable subsidies and dumping that may be causing (or threatening to cause) material injury to an industry in the United States, and (2) potential circumvention of existing antidumping or countervailing duty orders. The task force must make recommendations with respect to initiating antidumping or countervailing duty investigations and circumvention inquiries.