Serbian media reports say the country's richest businessman, Miroslav Miskovic, has been arrested in connection with a privatization deal.
The Interior Ministry says Miskovic, his son, and six other business people were detained on December 12.
Prosecutors were expected to rule on their pretrial detention within 48 hours.
The charges relate to a suspected embezzlement scheme worth an estimated $40 million.
Miskovic made his fortune as an ally of former Serbian leader Slobodan Milosevic during the 1990s.
His wealth was estimated at more than $2 billion in 2007, although it is believed to have shrunk since then.
High-ranking Serbian officials have been linked to several corruption scandals in the past, but there have been no major convictions.
Serbia's current government launched a crackdown on corruption after it came to power in July.
Based on reporting by dpa, TV B92, vesti.rs, and RFE/RL's South Slavic Service