Registered capital of SBB is ~$12.5m Therefore they have to...

Registered capital of SBB is ~$12.5m
Therefore they have to allocate 10% of NPAT to a trust till it equals 50% of the registered capital... this is the statutory reserve requirement.
SBB have set aside $6.75m to the reserve.

It forms part of the cash equivalents and can only be accessed upon the liquidation of the company.
Therefore available cash equivalents for business use (or capital management) = $30m - $6.75m = $23 million.