The Financial Regulator has banned short-selling in Ireland's biggest financial institutions, in a bid to stop investors from profiting on share prices falling.
Authorities in the UK have implemented a similar ban, hoping to bring calm to the current market turmoil.
The US government is also considering a rescue plan to help banks with their bad debts as Wall Street rallied to its best day in six years as a result.
It follows one of the most dramatic weeks ever seen in the financial world.