A more thorough explanation:

OFFICE OF TAX-SHELTER ANALYSIS

The Office of Tax-Shelter Analysis is a department within the U.S. Internal Revenue Service that is responsible for identifying and investigating tax shelters that may be questionable. The OTSA was established in 2000 to ensure that taxpayers are not using tax shelters to avoid paying their fair share of taxes.

One example of a questionable tax shelter is a scheme that involves transferring assets to a foreign country to avoid paying taxes in the United States. Another example is a complex financial arrangement that is designed to create artificial losses for tax purposes.

For instance, a company may create a tax shelter by setting up a subsidiary in a tax haven country and then transferring profits to that subsidiary. This allows the company to avoid paying taxes on those profits in the United States.

The examples illustrate how some taxpayers may use tax shelters to avoid paying taxes. The OTSA is responsible for identifying and investigating these types of schemes to ensure that taxpayers are paying their fair share of taxes. By doing so, the government can collect the revenue it needs to fund important programs and services.