The court ruled that the prosecution lacked evidence to prove the charges of aggravated bribery as filed against four of the defendants.
Finnish broadcaster YLE initially reported that the court had nevertheless expressed doubts about the deal, but this was dismissed by the prosecutor on the case, Jukka Rappe.
The court said "the prosecution has not proved the case beyond reasonable doubt. This means there was not enough evidence," he told the STA in a phone conversation, adding that YLE had "caused misunderstanding" with its report.
In addition to the acquittals, the Finnish state was ordered to pay court costs amounting to EUR 1.2m, YLE and the Finnish press agency STT reported.
Slovenia's purchase of 135 APCs from Patria, which was the country's biggest defence deal, became the focus of corruption allegations in Finland, Austria and Slovenia soon after it was made in 2006. The deal was cancelled in September 2012 with only 35 APCs delivered to Slovenia.
It remains unclear how the verdict will impact on cases in Slovenia and Austria, where courts of first instance handed down guilty verdicts on bribery charges which are now being appealed by those accused.
In Slovenia former Prime Minister Janez Janša, army officer Tone Krkovič and Ivan Črnkovič, the boss of Patria's local partner Rotis, were found guilty at first instance on 5 June of charges related to the giving and receiving of gifts.
In Austria Hans Wolfgang Riedl, a middleman, was sentenced to three years in prison by a Vienna court in April for bribery, fraud and tax evasion for his role in channelling hundreds of thousands of euros in Patria kickbacks to Slovenia.
Reacting to the ruling in Finland, Črnkovič said that he expected the evidence from Finland used in the trial in Slovenia to now be excluded. It is clear that the case must be dropped, he told the STA today.
Črnkovič said that this would leave some people in Slovenia with their "heads hanging low", pointing foremost to the judge in the trial before the Ljubljana Local Court, who he believes is responsible "for the biggest injustice in the history of justice".
This was echoed by Janša's lawyer Franci Matoz, who believes the verdict will influence proceedings in Slovenia.
He pointed to the Finnish evidence used in Slovenia and the fact that the prosecutor in Slovenia had repeatedly argued that if a bribe had been given somebody must have accepted it. The Finnish court concluded that bribes were not paid nor promised, he said.
Meanwhile, the Slovenian prosecution did not want to comment on the verdict in Finland beyond saying that each country's judiciary was independent in handling the case according to local laws.
Opposition Democrats (SDS) leader Janša, who has maintained his innocence and labelled the case against him a political show trial, took to Twitter to respond, saying that Finnish courts could not be swayed by Slovenian political godfathers.
"The reach of [the Ljubljana borough of] Murgle does not go all the way to Finnish courts," he said using the term which he has used for what he says are political godfathers who control the centre-left in Slovenia.
The Finnish prosecution accused of bribery former general manager Jorma Wiitakorpi, former executive vice-president of Patria Vehicles Heikki Hulkkonen, Patria representative for Slovenia Reijo Niittynen, former marketing and marketing chief Tuomas Korpi, and former chief financial officer Kai Nurmio.
Responding to the acquittals, Patria said in a published statement that the "decision was as expected", adding that it must still review its details.
STT journalist Merje Akerlind said that the verdict was issued on more than 80 pages, with the court highlighting among other things that Finnish law does not recognise the crime of abuse of office and that even if that took place in Slovenia, it could not be prosecuted in Finland.
The court also highlighted that first-instance guilty verdicts in Austria and Slovenia do not mean that Patria representatives necessarily committed crimes, Akerlind said.
According to her, the ruling also states that it remains unclear whether Črnkovič, Krkovič and Jože Zagožen (a former member of the SDS, who died last year) had acted as middlemen to Janša and whether Krkovič and Janša had known about any promises of bribes.
The decision by Slovenia to purchase Patria's APCs was taken by a special selection commission, but there is no proof that Slovenian players had influence over the commission. While Krkovič could have influenced the list of technical demands in the tender, there is insufficient evidence to prove this, the ruling finds as cited by Akerlind.