It is not acceptable for the wealthy to hide money overseas to avoid tax, Jourova told the newspaper, and she is re-examining EU rules to see how they can be improved.
"We have to look at the accessibility of the beneficial ownership registers and also look at the rules for trusts. We need to further increase transparency," she told the Financial Times.
Ordinary citizens work hard and pay their taxes, and cannot understand why it is still possible for some people to hide their money from tax authorities, Jourova said.
"We cannot tolerate this – it is a question of fairness and justice in the EU," she told the Financial Times ahead of a meeting of EU finance ministers.
The UK, Germany, France, Italy and Spain announced this month that they will automatically exchange information on beneficial ownership to show who really owns and controls their companies and trusts. These so-called 'G5' economies have also written to their colleagues in the G20 urging them to adopt the same measures.
The announcement was described as "ground-breaking" by UK chancellor George Osborne, who said that it would ultimately make it more difficult for firms to "dodge tax or funnel corrupt funds".
According to the G5 finance ministers' letter, beneficial ownership information relating to "companies, trusts, foundations, shell companies and other relevant entities and arrangements" will be exchanged "in a fully searchable format" and will include "information on entities and arrangements closed during the relevant year".
The exchange will initially operate as a pilot, during which participating economies will explore the best way to exchange this information with a view towards ultimately developing a "truly global common standard". This work should be led by the global Organisation for Economic Cooperation and Development (OECD), alongside the Financial Action Task Force. Ultimately, the system should develop into one of "interlinked registries containing full beneficial ownership information", according to the letter.
The OECD has already developed a common reporting standard (CRS), through which more than 90 countries will automatically exchange offshore bank account information with other jurisdictions on an annual basis. The first exchanges will take place in 2017 with more countries due to begin participating in 2018.
Since 6 April, UK companies and limited partnerships have been obliged to keep a register of 'people with significant control' (PSCs). PSCs are individuals who hold more than 25% of a company's shares or voting rights, have the right to appoint a majority of directors or have the right to exercise, or actually exercise, significant influence or control over the company. Companies will have to supply the information to Companies House from 30 June 2016 when they file the company's confirmation statement - the replacement for the annual return. A company's PSC register can be inspected free of charge by those with a 'proper purpose' and most of the information supplied to Companies House will be publicly available.
Other major economies have committed to introducing similar registers which will be accessible to 'competent authorities' and other limited categories of people with a legitimate interest in accessing the information.
The UK is also proposing to introduce a register of offshore companies owning UK property or participating in government contracts. A consultation on the proposals closed earlier this month. It proposed that foreign companies be required to provide information on their beneficial ownership before they were able to buy land/property in England or Wales or enter into public procurement contracts in England. It is not yet clear whether the requirement to provide beneficial ownership information will be applied to foreign companies that already own property or land in England and Wales.