A Spanish court ruled Thursday that a group of businessmen who duped many small-scale investors into staking their life savings on a supposedly high-yield venture based on postage stamps that in fact was no more than a pyramid-sales fraud should serve jail time.

Spain's National Court made public its verdict in the case of a company that sold allegedly rare stamps to investors as part of a Ponzi scheme that eventually wiped out the savings of more than 150,000 customers, in which it sentenced the company's former executives to various prison terms for aggravated fraud, money laundering, false accounting, bankruptcy fraud and tax crimes.

The ruling, which was accessed by EFE, said that the former top leadership of Afinsa was required to enter prison within the 10 days following the decision, which was made late on Wednesday.

According to the judges, Afinsa's clients were swindled by sales representatives who recommended they persuade relatives, friends, neighbors and acquaintances to join the scheme woven by the company's management by investing in philatelic products.

In exchange, Afinsa promised to re-buy the stamps at a higher price, a profit that derived from the company's constant revaluation of assets through pyramid sales.

The court said that this business model was "untenable," since Afinsa's investment was minimal and generated costs that increased its deficit equity, as demonstrated by the black hole in accounting of 2.6 billion euros ($3.2 billion) that prompted a police operation resulting in the arrest of Afinsa's top brass in 2006.

Afinsa's ex-president, Juan Antonio Cano, was sentenced to eight years and seven months in prison, while the company's founder, Albertino de Figuereido, his son, Carlos, and Afinsa's former CEO, Vicente Martín, were all condemned to more than eight years' imprisonment and fines of over 100,000 euros each.

In addition, Afinsa's ex-accountant, Emilio Ballester, was sentenced to eight years and four months as an accomplice to the crimes, while the person responsible for supplying the stamps, Francisco Guijarro, was handed a two-year sentence and a fine of 17.7 million euros for money laundering.

Guijarro, who went from being unemployed to amassing a fortune of more than 30 million euros in less than five years thanks to the massive scam, became Afinsa's sole stamp supplier between 1998-2003.

Police found 10 million euros in 500-euro bills hidden behind a freshly-built gypsum partition wall at his lavish mansion in northern Madrid.

The system used by the company consisted of recruiting small investors, often elderly people, who would pay small sums for stamps based on the promise of a 6-percent annual interest and the assurance that the products would rise in value as time went by.

Around 80 percent of the victims _ who never saw their stamps _ invested no more than 20,000 euros, while only 0.0001 percent put more than a million euros into the venture.

The ruse succeeded because the word-of-mouth recommendations by investors, encouraged by Afinsa, made the company gain new participants at a ballooning rate, thus enabling the payment of interest to original clients through revenue paid by new investors; this was tantamount to a classic Ponzi scheme.

In the summer of 2005, however, a United States broker named Louis Corrigan, who worked for the Atlanta-based hedge fund Kingsford Capital, sent a letter to the Spanish attorney general in which he denounced Afinsa's fraudulent activities.

On May 9, 2006, Spanish authorities carried out "Operation Atrio" against Afinsa and a similar philately company, Fórum Filatélico, after the country's tax agency found that both businesses had committed several fiscal crimes.

At the time, Afinsa had all the appearance of a blue chip company: it counted some 175,000 clients, possessed 100 offices spread out around the world, employed 2,600 people and showed a profit of 51 million euros; furthermore, Fórum Filatélico boasted 202,000 customers, 281 employees, 1,345 agents, five branches and 84.2 million euros in profits.

Spain's anti-corruption prosecutor said that the stamps' prices, which were set by the companies, were extremely overvalued, with some of the ones sold by Forum Filatélico being prized at 13 times their market value. In the case of Afinsa, many of the stamps they were peddling turned out to be fake.

Afinsa often bought the stamps from Guijarro at 8 percent of their value listed in philately catalogs and re-sold them at a monstrous profit of up to 1,150 percent. Just between 2000-02, it spent 57.88 million euros on the stamps and sold them for 723.55 million euros.

After a lengthy trial that stretched for almost a decade, Afinsa's executives were convicted by the national court in July 2016 and sentenced to up to 12 years in prison, although the Supreme Court later reduced Cano's sentence to only eight years.

Meanwhile, the separate (albeit related) trial focusing on Forum Filatélico started in Sept. 2017 and is expected to drag on until at least the spring of 2018.