Cristina de Bourbon, 49, was charged with 16 others including her husband of siphoning off public funds worth €6.1 million ($7.6 million) through the Nóos Institute.
Three judges from a court in Palma de Mallorca in Spain's Balearic islands will take a decision on Friday on whether to accept her plea made on July 2nd.
The charitable organisation was headed by Cristina's 46-year-old husband Iñaki Urdangarin, a former Olympic medal-winning handball player, between 2003 and 2006.
Cristina sat on the board of Nóos and Urdangarin was its chairman.
Investigators suspect that a separate company jointly owned by the couple, Aizoon, served as a front for laundering embezzled money.
Questioned in court in February, Cristina said she had simply trusted her husband and had no knowledge of his business affairs.
A mother of four with a master's degree from New York University, Cristina was once considered untouchable as a member of the royal family.
But the so-called Noos affair fanned public anger against the monarchy and ruling class during the recent years of economic hardship in Spain.
Urdangarin and Cristina have been excluded from royal activities since 2011.