MADRID — Spanish judges set bail of more than $38 million on Friday for a billionaire and friend of former President Hosni Mubarak of Egypt.

The billionaire, Hussein K. Salem, was arrested in Spain this week in what was considered a breakthrough for Egyptian prosecutors. They are seeking his extradition to try him in corruption cases relating to what they say are sweetheart deals that enriched him and Mr. Mubarak.

The Spanish charges of money laundering, fraud, bribery and corruption are related to the use of money that Mr. Salem is accused of obtaining illegally in Egypt, the police in Spain said.

The case is closely tied to accusations of corruption against Mr. Mubarak and other former officials ousted in Egypt’s revolution in February, and could open a window on Mr. Mubarak’s hidden foreign holdings, which are thought to exceed several billion dollars.