The Commons can't remain intact until all company assets are distributed to each Class in the following order. The Government/IRS is first, then there are the Secured Debt holders, next is Unsecured Debt Holders, followed by Unsecured Creditors - after all of the above groups are 100% satisfied what they are owed or repaid - then comes the Equity Holders first comes the Preferred shareholders and the last is the Common shareholders.
Keep in mind that the common shares can't remain intact if any of the above Classes are impaired.
The SEC has a warning about investing in Q stocks.