IPSA is responsible for: setting the level of and paying MPs' annual salaries; paying the salaries of MPs' staff, drawing up, reviewing, and administering an MPs' allowances scheme; providing MPs with publicly available information relating to taxation issues; and determining the procedures for investigations and complaints relating to MPs.
Upon its formation IPSA took over some of the functions previously undertaken by the House of Common's Fees Office, as well as some of the staff who previously carried out these functions.