For the conspirator theorists out there: SBB earns 0.3% on its...

For the conspirator theorists out there:
SBB earns 0.3% on its holdings of cash.  Refer 2015 December half year accounts notes to the accounts 29.3

Independent check:
http://china.deposits.org/
http://china.deposits.org/savings-accounts/

Savings account rates: 0.3-0.385% interest rates depending on bank.  Banks such as Bank of China: 0.3%

Therefore nothing "funny" about the low interest being paid.
SBB doesn't engage in active treasury management thats all.  Maybe also with China, they prefer the security of just leaving it in a bank savings account, rather than other types of deposits which might be
a) more risky (remember this is China)
b) gives them flexibility to tap into that money at any point in time
c) gives them more flexibility when negotiating with third parties (see my bank balance: its got this amount of money in it)

Who knows. But there is no evidence of fraud by linking interest earned to current cash holdings.

Also note in the Dec half year notes 29.3 the rate on borrowing money.  Hence why borrowed money has been paid back over the years.