In the U.S., the terms used for bankruptcy are "voluntary" and "involuntary." Here is a sample:

http://www.yourdictionary.com/bankruptcy

involuntary bankruptcy
A bankruptcy proceeding initiated by a creditor to legally declare a debtor to be bankrupt and to impound all of the debtor’s non-exempt property, distribute it or its proceeds to the creditors, and extinguish the debtor’s liability.
voluntary bankruptcy
A bankruptcy proceeding voluntarily initiated by a debtor who files a petition with the bankruptcy court to be legally declared a bankrupt and, during the proceeding, surrenders his property in order to discharge his debts.

You may wish to rephrase in order to switch from the adverbial form to the adjectival form, i.e., to "declare voluntary or involuntary bankruptcy," for the sake of better readability.