The Spanish government is due to unveil a new raft of austerity measures amid mounting concerns over the country's economic future.
Many think the grim measures, which are expected to include higher taxes and changes to pensions, will be a precursor to a request for help from the European Central Bank.
Recession-hit Spain has come under pressure to tap an ECB bond-buying programme, designed to keep a lid on the country's borrowing costs.
So far the government has been reluctant to ask for help for fear of the conditions attached.
Many investors think the measures, to emerge alongside a draft 2013 budget, will pre-empt those conditions, making it easier for the government to request help.
The package comes in the wake of a violent protest in Madrid and big falls in Spanish stocks.