MADRID (AP) — Former International Monetary Fund chief Rodrigo Rato is apologizing for his crimes as he starts a 4½-year prison sentence for misusing a Spanish bank's corporate credit card.

Rato said as he entered a prison outside Madrid on Thursday, "I accept my obligations to society, I admit the mistakes I may have made and I ask forgiveness from society and the people who may have been affected or felt let-down."

The National Court last year convicted him of unlawful misappropriation of funds during his 2010-12 leadership of Bankia, a bank that was later bailed out. Rato had denied that the credit cards were used for irregular and undeclared expenses.

Rato was IMF chief from 2004 to 2007 and previously a leading figure in Spain's conservative Popular Party and Spanish economy minister.