4-5%. If buying from banks,  need to be priority customer.

In my opinion if one is getting 4%+, might as well go for FD. More secure. Also if 5%, better ignore it as ASNB is giving min 6% for their fixed price fund.

I don't invest in retail bond because I personally feel the concentration risk is too high and return is just average. For fixed income, I am more interested in bond funds and P2P Lending.
As you mentioned yourself, there is always a first. Just because it has not happened before does not mean it will never happen. The world is constantly changing. In fact, 6% is the lowest historically up till now. It was higher in the years before. In the past few years, the return seemed to be on a downtrend. What is there to stop it from going below 6% if the stock market is not doing well? Hence, no such thing as minimum return.

ASNB is super popular among Malaysians because it is one of the best low risk and low fees investment options available. Not because of minimum 6% return and guaranteed higher than FD return. There is no guarantee.