Commonwealth Bank of Australia (ASX: CBA) shares have been on a tear over the past half year.

Six months ago, shares in the S&P/ASX 200 Index (ASX: XJO) bank stock were trading for $98.09. Today those same shares are worth $118.70, up 21%.

March even saw CBA shares break into new all-time highs, closing at $121.45 on 8 March.

And despite numerous analysts cautioning that its valuation is looking stretched, CommBank could continue to outperform, in part due to its market-leading adoption of artificial intelligence (AI).

Perpetual Investment Management portfolio manager Anthony Aboud believes AI can benefit every ASX 200 bank stock.

But he calls out CBA shares as likely to gain the most, with Australia's biggest bank quick to embrace AI. In FY 2023, the bank's information technology expenses increased by 8% year on year.

"If you were to believe that there would be cost out efficiencies through AI initiatives, CBA has historically been the one bank which could be able to capitalise on that first," Aboud said (quoted by Bloomberg).

As CBA moves to automate more of its processes, he said this will bring down costs, which will come as good news to shareholders.

And those costs are sizeable. According to Bloomberg data, CBA spent north of $7 billion in FY 2023 on its workforce.

In February, CBA shares got a lift after the bank reported it was rolling out cutting-edge AI technologies developed by Microsoft Corp (NASDAQ: MSFT).

As we reported at the time, CBA's group chief information officer, Gavin Munroe, said the bank's software engineering teams had been given access to Microsoft's GitHub co-pilot. And he said their productivity was rocketing as a result.

Also offering some potential tailwinds for CBA shares is the outlook for lower interest rates.

Aboud said that as the RBA starts to cut the official cash rate, "Margins will probably stay stable" for CBA and the other big banks.

 "The probability of bad debts increasing with lower interest rates is probably lower, so they'll probably do OK in that environment," he added.

Indeed, if CBA opts not to pass on the full amount of any future rate cuts to borrowers, it could boost earnings and profits in the year ahead.

Investors are also increasingly optimistic inflation will come under control without Australia entering a recession.

As always, before buying CBA shares or another ASX stock, be sure to do your own research first, or reach out for some expert help.