National Australia Bank (NAB) has dropped to the bottom of the pack for satisfaction levels among business customers.
A monthly survey of satisfaction among the big four's business clients shows NAB stuck alone in last place, despite being Australia's largest business lender.
NAB had an average satisfaction rating of 7.0 in September, while Commonwealth Bank (CBA) came out on top with a rating of 7.6, according to the DBM Consultants' Business Financial Services Monitor (BFSM).
Westpac (WBC) was ranked second with a rating of 7.5.
ANZ (ANZ), which was previously tied with NAB, moved up to third after recording its highest ever rating in the four year history of the survey - 7.2.
DBM Consultants Director Maria Claridad said ANZ had been improving its satisfaction rating during the past few months.
The bank had experienced the biggest improvement in the micro-business category, thanks in part to its new focus on start-up businesses, she said.
"ANZ's pledge to focus on start-up businesses, which was announced in April, may be helping them continue the improvements that they started to see in July of last year," she said.
The BFSM is based on interviews with 20,000 businesses a year.