Prosecutors from Spain's top criminal court accuse the striker, his father, Barca's ex-president Sandro Rosell and the club itself of concealing the cost of the multi-million-euro transfer from Brazilian investment fund DIS.
DIS held 40 percent of the 24-year-old's sporting rights when he played at Brazil's Santos club and has claimed it was cheated of its real share of the transfer due to parallel contracts that Barcelona and Santos allegedly used to hide the total cost.
The case first came to light after fans and members of Barcelona launched an internal complaint, leading eventually to the resignation of Rossell.
Santos -- where Neymar started his career -- received 17.1 million, 6.8 million euros of which went to DIS.
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However, Spanish judicial authorities have estimated the number of simultaneous deals in the transfer amounted to at least 83.3 million euros -- with the difference allegedly going to Neymar and his family, and Santos.
The Brazilian football star and his father have in the past defended themselves in the media.
"Before saying nonsense -- that we hid this, or hid that -- they should prove it," Neymar told Brazilian TV station Globo in February, when he was called to give evidence to a judge in Madrid.
Prosecutors want Neymar, his father Neymar Da Silva Santos, Rosell and FC Barcelona itself to be tried for "private corruption among individuals."
They also wants Rosell, FC Barcelona, Brazil's Santos and its president to be tried for "fraud."
Neymar's mother Nadine, meanwhile, could also be tried for having profited financially from the alleged fraudulous transfer.
The Brazilian star has already given evidence to a judge in Spain as part of the probe, as has his father.
Investigators in Brazil have also launched proceedings against the football star and his father over the same case.
Brazil's federal prosecution service has accused them of forging contracts to pay less tax.
Last September, Brazilian authorities froze $47 million worth of the player's assets pending investigations.