The big four banks are popular options for many Australian investors. But are Commonwealth Bank of Australia (ASX: CBA) and National Australia Bank Ltd (ASX: NAB) shares worth buying this week?
To find out, let's take a look at what analysts are saying about these two big four bank shares courtesy of The Bull. Here's what you need to know about them:

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CBA shares
Red Leaf Securities has named Australia's largest bank as a hold this week.
It highlights that CBA is the highest quality franchise in Australian banking and has resilient earnings.
However, with its growth moderating and mortgage competition intensifying, Red Leaf Securities has concerns. This is especially the case given the significant premium that CBA shares trade on compared to both local and international peers.
Commenting on its hold rating, Red Leaf Securities said:
CBA remains the highest quality franchise in Australian banking, supported by its dominant deposit base, strong digital ecosystem and industry leading profitability. Earnings remain resilient, but growth is moderating as mortgage competition intensifies and credit expansion normalises.
Credit quality is stable and dividends remain highly reliable, reinforcing its defensive appeal. However, the key issue is valuation, with the stock trading at a significant premium to domestic and global peers. Much of the quality and stability is already priced in, leaving limited upside without a material macro or earnings surprise to the upside.
NAB shares
The team at Catapult Wealth isn't feeling upbeat on the investment opportunity with NAB shares.
With NAB recently delivering a disappointing half-year result for FY 2026 and Federal Budget policies potentially weighing on loan and property price growth, Catapult Wealth thinks that NAB could struggle to deliver on the market's expectations in the near term.
As a result, the financial services company has named NAB as a sell this week.
Commenting on the big four bank, Catapult Wealth said:
The bank's first half result in fiscal year 2026 was underwhelming, in our view. Investment loans account for about a third of residential lending. Proposed changes to negative gearing and capital gains tax are likely to reduce loan and property price growth, in our view. Given higher interest rates and affordability pressures, NAB may struggle to deliver the growth needed to support current expectations.