I've had a look through the ASX listing rules, available on the ASX website. Rule 3.8 covers buy-backs, which documents have to be lodged and by when.
I still can't work out if companies have to follow the same process for interest rate securities as they do for shares. I do know that the market has to be notified if any securities are cancelled after buy-back.
There would be nothing stopping B&B, a suitor or indeed anyone else entering into an over-the-counter (OTC) call option on BNBG with a broker and then exercising the option in the future when they wished to buy the securities. This would be one way to achieve the same outcome.
BNB Price at posting:
29.0¢ Sentiment: None Disclosure: Held