Spiro highlighted the case of Bankia, which was forced to accept over 20 billion euros ($27.2 billion) of European aid after clocking up massive losses as a result of the country's dramatic property crash. Over 30 Bankia board members were investigated over allegations of fraud, price-fixing and falsifying accounts at the lender.
"Weak regulatory oversight contributed to Spain's financial crisis and is evidently still a problem, despite the fact that Spain has been under intense external scrutiny over the past several years," Spiro added.
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"One would have hoped that the collapse of Spain's housing bubble, and the ferocious criticism of Spanish banking and stock market regulators that ensued, would have put an end to these kind of scandals Unfortunately this is not the case."
Before its shares were suspended, Gowex was listed on Spain's alternative stock exchange, the Mercado Alternativo Bursatil (MAB).
The company had come to be seen as something of tech star, with its share price rising around 25 percent between January and its peak in April. However, after Gotham City's report on July 1, its stock plunged close to 60 percent – pulling a number of other MAB-listed companies lower with it.
In a statement on its website, published before it filed for bankruptcy on Thursday, Gowex said it was preparing a response to Gotham City's "baseless allegations".
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The MAB, meanwhile, insisted that "grave irregularities" at Gowex should not cast doubt on the index, which it said was "indispensable" to the Spanish financial system. In response to Gowex's downfall, Spain's financial regulator, the CNMV, said it was looking at revising the way it monitored MAB companies and would assess whether other firms on the index had been engaged in similar market abuse.
But Predrag Dukic, senior equity sales trader at CM Capital Markets in Madrid, told CNBC there was no doubt the saga had done "significant damage" to both the MAB and Spain's stock markets more broadly.
"Quite a few companies (have announced) they are going to leave the MAB. No doubt, once the credibility is lost, it is very difficult to recover it," he added.
Dukic stressed, however, that although Gowex's accountancy irregularities were able to go unnoticed on the MAB, this situation was unlikely to occur at one of Spain's international blue chips. Companies like Banco Santander, BBVA and Telefonica, for instance, have to obey international accounting standards and are audited regularly.
"At the end of the day, less-regulated markets such as the MAB depend on the integrity of individuals running the firms. As long as there is an incentive to cheat, there will be cheaters," Dukic said.