New Delhi, Aug. 19 -- UnitedHealth Group is challenging an Internal Revenue Service proposal that could significantly increase its taxable income over transactions involving a foreign subsidiary, putting the healthcare giant in the latest high-profile transfer pricing dispute between a US multinational and the tax agency.

The dispute covers UnitedHealth's tax years from 2017 through 2020, according to company filings cited by Fortune. The IRS has proposed adjustments that would raise the company's taxable income for each year and could pursue similar changes for subsequent tax years.

The case centres on transfer pricing, the way multinational companies set prices for transactions between related businesses operating in different countri...