Q&A: Spanish bank deal
Early market reaction to the plan to help Spain with an estimated 100bn euros ($125bn; £80bn) has been positive. Spain says the money is neither a rescue nor a bailout.
Whatever it is called, how will the money help and will it stop the eurozone crisis escalating?
Is the money enough to save Spain?
Firstly, the amount of money being given to the banks is not yet known. Independent auditors are looking into how much the banks need and they are expected to report back later this week (beginning 11 June).
It is known that the banks are sitting on massive losses - some say it could be as much as 180bn euros - but the 100bn-euro figure is a good guide. Just saving Bankia, Spain's fourth-largest bank, will need 19bn euros, with other regional banks also needing large sums.
Not all of the banks are in the bad basket. The International Monetary Fund said a large part of the banking sector, including Santander and BBVA, was well-run and resilient.
Spain was overbanked, but it has begun to restructure, with many of its smaller, weaker banks merging or rescued. Staff and outlets have been cut back by more than 10%.
But the economy itself is weak, with Spain suffering its second recession in three years.
The theory is that if the banks are healthy, they will lend to businesses and individuals and lubricate economic activity, but as we have seen elsewhere, they may of course not do this.
In any case, there is a problem with high unemployment - 24% for the adult population and more than 50% for the under-25s - so the number of people who are good borrowing risks is limited.
On top of that, many have high debts already, particularly those who invested in Spain's soaraway property market.
Values are 20% below their peak - at the least - meaning investors are sitting on huge losses, repaying loans for assets worth a fraction of what they bought them for or even downright defaulting.
If Spain's recession gets worse, so will the number of people unable to pay back loans and mortgages.
There is another problem, which is the structure of the support fund itself. The money is being passed through a government agency to the banks, meaning the debt will sit on the government's books.
Spain's debt-to-GDP ratio is relatively low, at 70%, but the banking package could take it closer to 100%.
With a weak economy, raising tax revenue to balance the books is tricky. And if markets do not have confidence in the deal, borrowing will be expensive.
Has Spain been given a bailout with fewer strings than the others?
Germany, which backs a large amount of the money going to Spain, said the package would have strings and would be overseen by the same "troika" - made up of European Commission officials, the European Central Bank and the International Monetary Fund - that monitors Portugal, Ireland and Greece.
In some quarters, these officials have acquired the nickname of the "men in black", and Spain was keen to avoid their regular visits to oversee economic affairs.
The Germany finance minister said because the deal was about restructuring the banking sector, the troika would also be joined by officials from the European Banking Authority.
The conditions that will be monitored have not been set out yet.
Spain - as its government has been keen to point out - is seen as responsible in a way that the other three countries, Greece, Portugal and Ireland, were not.
Not only has Spain has begun to restructure its banking sector, but it is already undertaking austerity measures.
Spain's budget this year has been described as the most austere in 30 years and includes tax rises and spending cuts worth 27bn euros.
Who is paying for this bailout?
The loan will come from eurozone funds set up to help members in financial distress: the European Financial Stability Facility (EFSF) and/or the European Stability Mechanism, which comes on stream in July and will run in parallel with the EFSF until that expires in 2013.
The EFSF raises money on open markets and is backed by the 17 eurozone members, so in theory, the funds they offer are themselves loans provided by investors.
It is seen as one of the most reliable borrowing organisations in the world and has a top credit rating from the agencies.
In the event that a country fails to pay back any loan, guarantees would be called in from the remaining guarantors - the 17 members of the eurozone, graded according to their own economic strength.
The EFSF was designed to be temporary and will be replaced by the European Stability Mechanism (ESM).
It will have a lending capacity of 500bn euros, but it still needs to be ratified by a majority of the 17 member states.
How much will this shore up confidence?
We could leave this at the simple answer: Not enough.
That is the most constant theme from initial comments from analysts and investors.
Although markets rallied the moment they got the chance to trade, it was not by a resounding amount, with gains typically of up to 2%.
Capital Economics said that Spain's banking bailout might help to pull the country away from the centre of the eurozone storm, but it doubts that will be the last of the support for Spain.
Economist Megan Greene says a bailout is very unlikely to succeed in drawing a line under concerns about Spain's solvency and in the absence of growth, a bailout of the banks will be followed by a bailout of the state.
Ruth Lea, at Arbuthnot Banking Group, calls the help for Spain "another sticking plaster on the eurozone's fractured edifice" and says it is no solution to the crisis.
Eyes are also shifting east to Italy, which has big debts and an economy shrinking at the same pace as Spain.
At the start of the year, that was considered a far riskier bet than Spain, a position that reversed amid the focus on Spain's banking woes. But investor demand for financing Italy's debt is waning, too.
And Greece - which is holding elections this weekend that could elect an anti-austerity government - may yet provide more unwelcome surprises.
What more can the euro area countries do?
Some member countries think the only way to shore up the eurozone is to draw the countries closer together so it operates more like one big country, with a single set of rules and regulations, than a collection of countries.
That would mean the collective debt being shared by everybody, so the weak are shielded and backed up by the strong - a bit like adding your teenage offspring to your car insurance, rather than making them apply for their own.
Most of the strength would be provided by Germany as the biggest economy.
But for it to be willing to stand guarantor it would want a bigger say in how countries set their budgets so they can't live beyond their own means.