Arm Holdings PLC shares rose 4.76% to $263 in Wednesday after-hours trading after gaining 3.93% in the regular session to close at $251.06. The move followed an expanded collaboration with IBM to bring Arm architecture to future IBM Z and LinuxONE mainframe platforms, creating the companies’ first jointly developed dual-architecture processor. Each core will be able to run both IBM and Arm instruction sets, allowing Arm-based Linux systems to operate alongside z/OS and traditional Linux workloads on unified hardware. Investor interest was also supported by Arm’s newly unveiled AGI CPU for AI data centers, which has secured more than $2 billion in pre-orders. The chip is being co-developed with Meta and is Arm’s first self-designed data center processor after 35 years as a licensing business. Raymond James raised its price target to $641 from $565 while maintaining an Outperform rating. Arm’s first-quarter earnings of 45 cents per share and revenue of $1.29 billion exceeded consensus estimates of 40 cents and $1.26 billion, respectively. The stock has gained 79% over the past year, with a market capitalization of approximately $268.13 billion, a 52-week range of $100.02 to $452.61 and an RSI of 43.79.