Samsung Electronics posted a 15-fold jump in quarterly chip profit on Thursday, powered by the AI boom, but its shares tumbled as investors balked at a lack of fresh shareholder-return plans and an outlook that lagged rival SK Hynix’s.

Samsung shareholders’ hopes were up as SK Hynix on Wednesday reported better-than-expected earnings and an upbeat outlook while spelling out plans to return about $75 billion to shareholders this year.

“SK Hynix did quite a lot more than expected yesterday … it went beyond ⁠market expectations, ​but Samsung Electronics hasn’t really changed anything from the guidance it gave before,” said Lee Min-hee, analyst at BNK Investment & Securities.

SK Hynix said on Wednesday its dynamic random-access memory (DRAM) and high-bandwidth memory (HBM) chips were sold out through 2029 and the chip shortage would persist to 2030, helping ease market concerns that AI-driven chip earnings could lose momentum.

Samsung said its HBM supply has been sold out for next year, with key customers…