There are several ASX blue-chip shares that dominate the S&P/ASX 200 Index (ASX: XJO) in terms of market cap.
Interestingly, the ASX 200 is one of the most concentrated developed-market indices on the planet.
According to VanEck, the top 5 securities account for 33% of Australia's benchmark index.
This means that when these companies rise or fall, they can heavily influence the broader performance of the ASX 200.
In the month of March, the ASX 200 index fell almost 8%.
This was the largest single-month fall in some time, heavily influenced by the conflict in the Middle East.
Let's look at how some of the largest blue-chip shares performed during this month.
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Commonwealth Bank of Australia (ASX: CBA)
CBA is Australia's largest company and largest bank.
The performance of CBA shares strongly influences many other equities, including financial and ASX 200 tracking ETFs.
Out of the big four bank shares, CBA was the best to own during the month of March.
CBA shares finished trading in February at $174.62 and finished March at $167.70 each.
In total, that was a 4.0% fall in March, significantly outperforming the 7.8% loss posted by the benchmark index.
The Motley Fool's Bronwyn Allen reported last week that CBA has drawn bull rally predictions from experts recently.
The report suggested CBA shares could rally to as high as $190 each.
This suggests that the recent pull back could be an attractive entry point for those seeking exposure to the blue-chip stock.
BHP Group Ltd (ASX: BHP)
BHP is Australia's largest blue-chip mining company, and is among the world's top producers of major commodities including iron ore, copper, and metallurgical coal.
It was hit hard during the month of March, falling approximately 15%.
The blue-chip company remains up 12% year to date, and has drawn positive outlooks from experts following March's sell-off.
Remo Greco from Sanlam Private Wealth has a buy rating on BHP shares.
In a note (via The Bull), he said the current volatility presents investors with an opportunity to buy this global miner at attractive prices.
Wesfarmers Ltd (ASX: WES)
Wesfarmers is Australia's largest blue-chip consumer discretionary company.
Its subsidiaries include household names such as Bunnings Warehouse, Kmart Australia, Officeworks, Priceline, and more.
Wesfarmers shares also underperformed across the month of March, falling approximately 9%.
Despite this fallback, Wesfarmers remains a strong defensive option for investors expecting more volatility this year.
How to target ASX blue-chip shares
For investors trying to hone in on ASX blue-chip shares, a viable option is the iShares S&P/ASX 20 ETF (ASX: ILC).
It is designed to track the performance of the 20 largest Australian securities listed on the ASX.
This includes the three companies listed above, as well as other banking and mining giants.
It has outperformed Australia's benchmark index so far in 2026, rising 4% compared to a 1.7% fall for the ASX 200.
