Called the Target Saver, the rate applies across the group (TMBL) including Teachers Mutual Bank, UniBank, Firefighters Mutual, Health Professionals, and Hiver. 

To attain the full rate, there is a $1,000 minimum monthly deposit required - savers also can't make any withdrawals and must have a positive balance at all times.

Should savers fail to meet this criteria in a given month the base rate of 0.01% p.a. applies.

Notably, the account features a maximum balance of $5 million; 5.50% p.a. at $5 million accrues $275,000 per year.

This would then attract the top marginal income tax rate of 45% and assuming no other income is earned would result in a net $180,583.

Deposits are backed by the federal government guarantee up to $250,000.

This account is outdone only by ME Bank's top rate of 5.65% p.a. available on its HomeME product, available exclusively on the 'ME Go' app, according to InfoChoice's product database.

It's also outdone by Macquarie Bank's 5.55% p.a. but that applies only for four months.

TMBL's move is also notable in that it happened in a non-RBA hiking month, while many of its top-rate contemporaries last increased in June.

As of June 2023 TMBL is the fifth-largest customer-owned bank in Australia, according to APRA data, with more than $10.7 billion in residents' assets.

Savings Account Leaderboard: 8 August 2023

Bank Top Rate % Per Annum Conditions
ME Bank 5.65 Deposit $2k/month into transaction account, grow balance, maximum balance $100k
Macquarie Bank 5.55 Four-month fixed intro rate, max balance $250k
Teachers Mutual 5.50 Deposit $1k/month, no withdrawals
ING 5.50 Deposit $1k/month, grow balance, 5 card transactions, max balance $100k
RaboBank 5.50 Four-month variable intro rate, max balance $250k
Bank of Queensland 5.50 Ages 14-35, deposit $1k/month, 5 card transactions, max balance $50k
Move Bank 5.50 Deposit $200/month, maximum balance $25k, no withdrawals

Source: InfoChoice Product Database