I don't understand the problem here, Sale and buy back is perfetly legal everywhere in the world, the challange is reporting.
You can sell and buy back as much as you want, but when it comes to reporting, the substance of the transactions take precedence over their form. To me this is a reporting issue to be dealt with by the institutions directors and their auditors.
Offcourse the regulators can reject the financial statements if they have evidence of misrepresentation of reports made to the public and penalise the errant directors/management and auditors accordingly.
"The purpose of bureaucracy is to compensate for incompetence and lack of discipline." James Collins