National Australia Bank Ltd (ASX: NAB) shares look to be caught up in the broader market selling action today.

Shares in the S&P/ASX 200 Index (ASX: XJO) bank stock closed up 0.2% on Friday at $34.17. In late afternoon trade on Monday, shares are swapping hands for $33.95 apiece, down 0.6%.

For some context, the ASX 200 is down 1.6% at this same time.

Year to date, however, NAB shares have underperformed the benchmark index, sinking 8.8% compared to the 4.3% loss posted by the ASX 200.

And Sequoia Wealth Management's Peter Day expects more underperformance from the big four Aussie bank stock in the months ahead (courtesy of The Bull).

Time to sell NAB shares?

"Group chief financial officer Nathan Goonan has resigned to take on the same role at competitor Westpac Banking Corp (ASX: WBC)," said Day, who has a sell recommendation on NAB shares.

Day added:

Goonan had only been in the CFO role at NAB since July 2023 and will leave later this year after meeting contractual obligations.

Goonan's resignation was mostly unexpected among other executive leadership changes. Investors can be apprehensive about executive leadership changes as it can lead to uncertainty about the company's direction.

Indeed, NAB shares fell 0.2% on 17 March after the bank announced Goonan's pending exit, and shares dropped another 2.0% the following day.

"NAB has good business momentum and is executing a clear strategy based on being better for customers and our colleagues," NAB CEO Andrew Irvine said on the day the executive team shakeup was reported. "We have great talent and leadership across the bank and I'm confident we will maintain momentum while we embed these changes."

Atop the potential uncertainty that Goonan's unexpected departure as CFO brings to the table, Sequoia's Day also pointed to NAB's declining cash earnings as a reason to sell the ASX 200 bank stock.

"In a first quarter 2025 trading update, cash earnings were 2% lower compared with the 2024 quarterly average in the second half. We have downgraded NAB to underweight," he said.

NAB shares closed down 8.1% on 19 February, the day the bank reported its quarterly results.

While earnings were down for the three months to 31 December, NAB reported a 3% increase in revenue, with expenses over the quarter climbing by 2% year on year.

It's also worth recalling that on 13 February — just last month — NAB shares closed at 18-year highs of $41.24.