Despite the heightened levels of volatility in April, the S&P/ASX 200 Index (ASX: XJO) managed to carve out a strong gain during the month.

The benchmark index rose 3.6% to finish at 8,126.2 points.

A key driver of this gain was the banking sector, which investors flooded back into following weakness in March.

And while all of the big four banks charged higher, the star of the show once again was Commonwealth Bank of Australia (ASX: CBA) shares.

During the month, Australia's largest bank rose so much it managed to hit a new record high along the way. This is certainly no easy feat when the share market has been so temperamental.

But then again, CBA and its shares are just built differently. Investors consistently ignore bearish broker recommendations to buy the bank's shares and end up being rewarded handsomely.

CBA shares in April

In April, the banking giant's shares were in fine form and delivered a gain of 10.4%.

To put this return into context, a $20,000 investment at the end of March would have turned into $22,080 by the end of April.

This latest gain means that CBA shares are now up almost 50% since this time last year.

As a comparison, the ASX 200 index is up approximately 7% over the same period. Both exclude any dividends paid during the 12 months.

Macquarie believes that April's strong gains were driven by investors seeking safe havens. It commented:

Bank valuations held up well in recent months as the sector was perceived as a relative safe haven during a period of global market volatility.

What's next?

Well, you may not be surprised to learn that brokers continue to believe that CBA shares are materially overvalued.

One of those is Macquarie, which has warned that the downside risks are significant. It said:

While we see limited risk in the upcoming reporting season, we believe medium-term earnings risks are skewed to the downside as lending competition intensifies and interest rates are likely to fall.

We continue to see downside risk in the medium term, particularly if current market expectations for rates are correct. Our current forecasts incorporate 100bps of rate cuts and only partly reflect recent moves in yield curves, noting further risk to FY26-27E earnings of ~5-10% if fixed-income market pricing is correct.

Macquarie currently has an underperform rating and $105.00 price target on its shares. This implies potential downside of over 35% from current levels.