As they set national policy on important issues such as climate change, tech monopolies, medical debt and income inequality, US senators have glaring conflicts of interest, an investigation by news website Sludge and the Guardian can reveal.

An analysis of personal financial disclosure data as of 16 August has found that 51 senators and their spouses have as much as $96m personally invested in corporate stocks in five key sectors: communications/electronics; defense; energy and natural resources; finance, insurance and real estate; and health.

The majority of these stocks come from public companies, and some are private.

Overall, the senators are invested in 338 companies – including tech firms such as Apple and Microsoft, oil and gas giants including ExxonMobil and Antero Midstream, telecom companies including Verizon, and major defense contractors such as Boeing – in the five sectors as categorized by Sludge.