Investor fears that Spain is poised to ask for a multibillion-euro bailout very soon rattled investors amid uncertainty about its impact on the markets.

Spain's conservative Prime Minister Mariano Rajoy has set out plans for economic reforms that aim to answer questions he's likely to get asked before a bailout materializes. Rajoy has learned from the experience of Greece, Ireland and Portugal that the process before a bailout is approved can be painful, even humiliating.

Spain is hoping a bailout won't lock it out of financial markets, as happened in the case of Greece and other troubled eurozone nations.

Investors, however, are far from reassured. Their nervousness stems from uncertainty over the results of an independent stress test Rajoy ordered earlier in the year to give the reform process a certain international credibility.

The results of the stress tests are unlikely to be fully clear before Sept. 28, when they are due to published, despite leaks and advance texts made available to banks and the media.

Analysts believe that any attempts to put a figure on Spain's bailout needs will be unrealistic before the stress test findings are revealed.

Rajoy ordered the stress test to prepare the ground for an international bailout while data about the size and scale of a rescue effort remained fluid.

Current estimates that the bailout may require up to $78 billion, based mostly on industry estimates, are by no means final. Spain's second largest lender BBVA cited the figure as speculation over the bailout's final outcome preoccupied bankers across the eurozone.

Spain's expected resort to a bailout is especially sobering for a government that continued to insist until recently it won't opt for a bailout.

An across-the-board recapitalization of banks is fraught with risks for Rajoy while the government waits to identify specific problems faced by each of the affected institutions. Without a clear assessment of the banking industry's current state the government cannot be confident the bailout to be injected into the ailing system will be money well spent.

Investors want to be assured that the bailout will lead to lasting reforms and won't be a temporary relief.

At the same time, they know that a bailout needs to be initiated sooner rather than later to ensure Spain's economy doesn't spin out of control.

Spain is hoping a bailout agreement can be negotiated and signed before the eurozone situation gets worse. That need to secure a bailout in a timely manner is felt equally in Brussels and in Berlin, where German Chancellor Angela Merkel faces the task of persuading her German constituents that a Spanish bailout is as important as measures to help Greece, Ireland and Portugal have been in the recent past.