Elections likely as GERB changes stance, rules out supporting a new government in the current parliament.
While Bulgaria, Croatia and Romania are a long way off from eurozone membership, they are still keen to benefit from closer integration.
Nikolay Nenchev is second minister to be charged since PM Borissov's government submitted its resignation on November 14.
Other members of Bulgarian cabinet to be questioned over exchange with Turkey that resulted in financial losses and public health concerns.
Bulgaria looks set for months of political uncertainty and horse-trading after parliament on November 16 accepted the resignation of Prime Minister Boyko Borissov.
Outgoing president likely to appoint caretaker government to pave way for early elections.
Register for free to read bne IntelliNews Magazine. You'll receive a free digital subscription.
If you have already registered, enter the information below with the same email you used previously and you will be granted immediate access.
Thank you. Please complete your registration by confirming your email address. The confirmation email has been sent to the email address you provided.
IntelliNews Pro offers daily news updates delivered to your inbox and in-depth data reports.
Get the emerging markets newswire that financial professionals trust.
"No day starts for my team without IntelliNews Pro" — UBS
Thank-you for requesting an IntelliNews Pro trial. Our team will be in contact with you shortly.