According to the BBC the massive bank, HSBC, has helped hundreds of its customers evade tax by colluding in maintaining secret bank accounts in many countries in the world. This should not come as a surprise because HSBC has wealth larger than the vast majorities of the countries in the world and in terms of power, money is usually more powerfully than armies and police forces, as numerous monarchs and world leaders have found to their cost throughout history.
If HSBC are guilty of these offences of conspiracy to evade taxes then it poses regulators with a problem. They can institute criminal cases and if HSBC is found guilty the courts can impose what sound to normal people as massive fines, but what are to the bank itself merely a cost of trading, like maintaining a branch or an IT system.
If courts impose the kind of penalties that HSBC would suffer if it were an ordinary person as opposed to a corporation, then that penalty would see HSBC out of acton and its ordinary depositors would suffer. there is no point in fining a bank if it means that the taxpayer has to bail out the bank.
Governments are party to blame for this state of affairs. Taxes can bee viciously high and governments need to moderate them. In addition governments ought to legislate to prevent banks, whose well being is unfortunately essential to the economy of the nations in which they operate, from undertaking work in the fields of tax planning. This means that such work would be done by much smaller businesses whose well being is not essential to the economy, and to whom punishment would be meaningful.