The firm alleges it was the victim when Barca signed the player, third in the latest world football player of the year poll, from Brazilian club Santos.
A judge in Madrid, acting on a request from the state prosecutor, ordered Neymar, his parents, former Barca president Sandro Rosell, incumbent Josep Maria Bartomeu and two former Santos officials to present themselves on Feb. 1 and 2.
Javier Faus, a former Barca vice president, was called to appear as a witness.
“The judge … believes that the prosecutor’s requests are ‘relevant, necessary and balanced’ for them to require an examination of the facts,” the court said in a statement on Wednesday.
Neither Barcelona, Neymar or any of the other defendants could immediately be reached for comment.
The club has said it acted “fully within the law” and rejected the accusations contained in the DIS suit.
The fund, which owned 40 percent of Neymar’s rights when he was at Santos, alleges it was paid far less than it was entitled to when the player agreed to join the Spanish and European champions in 2013.
The complaint was the latest twist to a saga that has also led to Barca, Rosell and Bartomeu facing trial for tax fraud.
Bartomeu was a vice president under Rosell when Neymar was signed in a complex deal involving multiple contracts.
Bartomeu, Rosell, who resigned over the allegations, and the club have been accused of defrauding the tax office of some 13 million euros ($14.1 million). All three have denied any wrongdoing.
Prosecutors have asked for a prison sentence of two years and three months for Bartomeu and 7-1/2 years for Rosell, plus fines and payments of outstanding taxes totalling more than 60 million euros.
The tax probe was launched after a club member questioned the figures given for the Neymar deal. Barca initially said they paid 57.1 million euros but later admitted the cost was nearer 100 million.
($1 = 0.9248 euros)
(Writing by Iain Rogers, editing by Jeremy Gaunt)