He revealed in an analysis of corporate filings of Shell and BP how the two oil giants had paid no corporation tax on oil and gas production in the North Sea for three years, while over the same period they paid out £44bn in dividends. Ungoed-Thomas also examined filings of government tax reliefs for the North Sea oil industry which were made under the Extractives Industries Transparency Initiative (EITI). The disclosures in October 2021 helped inform the debate as the oil giants faced mounting scrutiny over whether they should pay a windfall tax. The article highlighted research by Rystad Energy that found the UK was the most profitable country in the world for the development of oil and gas “mega-projects”.
In May 2022, Ungoed-Thomas revealed how the betting giants had been quietly lobbying the Treasury over proposed reforms of the industry. The disclosures were based upon documents obtained under freedom of information laws which showed the meetings between betting firm executives and officials from HM Treasury and Revenue and Customs. The meetings would not have been disclosed under the current transparency rules. The long-awaited white paper into gambling reform has been repeatedly delayed.
Ungoed-Thomas’ also revealed how concerns that buy now, pay later products were like a "runaway train", and were being offered to consumers for buying groceries, pet food and hot drinks.