In a Thursday note, analyst Andrew Kaplowitz put a bullish "Upside 90-day catalyst watch" call on Vertiv shares. Citi uses the "catalyst watch" tag when an analyst expects shares to perform well soon.

Vertiv shares jumped 6% in morning trading, hitting all time high.

Kaplowitz gave a relatively simple reason: "Increased conviction on robust data center infrastructure demand." Citi has said that it projects 56% average annual spending growth between 2025 and 2029.

Vertiv is an AI enabler: It makes critical infrastructure products that cool and power data centers. The company has said that its 2025 sales are expected to top $10 billion -- up from $8 billion in 2024 -- rising along with capital spending by data center hyperscalers such as Microsoft, Amazon.com, and Alphabet.

Vertiv stock traded as high as $169.38 in early trading on Thursday, before falling to $166, down 0.8%, while the S&P 500 and Dow Jones Industrial Average were down 0.3% and 0.4%, respectively.

Starting points for the stock help explain the early trading activity. Citi's call wasn't a contrarian move. Vertiv stock has been on fire lately. Coming into Thursday trading, shares were up 47% year to date and up about 55% over the past 12 months.

Still, Kaplowitz remains bullish. He kept his Buy rating on shares and raised his price target to $192 from $167. Overall, 83% of analysts covering Vertiv stock rate shares Buy, according to FactSet.

(The average Buy-rating ratio for stocks in the S&P 500 is about 55%. The average analyst price target is about $161 a share, a little below where shares currently trade.)

Barron's wrote positively about Vertiv stock in August 2024 when shares were around $80, arguing that the company would benefit from growth in AI computing. That's turned out to be the case. Shares were much lower back then, but Citi believes the story still has legs.

Gains have left Vertiv shares trading for about 35 times estimated next year's forecasted earnings, similar to a year ago.