Citi expects the global memory semiconductor market to remain in prolonged supply shortage through 2031 as AI systems move from conventional training and inference toward continuous learning, in which models train autonomously. The bank forecasts simultaneous demand acceleration for HBM (high-bandwidth memory), server DDR5 and enterprise SSDs from 2027, pushing DRAM supply-demand ratios to -8.7% in 2027 and -9.7% in 2028, while NAND ratios reach -6.1% and -5.5%. Citi interprets the HBM despec debate as a response to supply constraints rather than weaker demand, with chipmakers seeking to maximize accelerator shipments using limited memory capacity. HBM bit demand is forecast to rise 62% year over year to 75.157 billion Gb in 2027 and another 69% to 126.990 billion Gb in 2028. Demand from Broadcom and Google is also expected to expand sharply, while accelerating ASIC shipments could widen the HBM supply-demand deficit to -36% by 2028. DRAM demand is projected to grow 30.2% in 2027 against 18.8% supply growth, and server DRAM demand is expected to increase 51% to 341.7 billion 1Gb-equivalent units. In NAND, eSSD demand is forecast to rise 52.9%, while Samsung Electronics' NAND production capacity is expected to decline 4.7%. Citi predicts DRAM and NAND prices will rise 23.1% and 45.3% in 2027 after surging 242.4% and 236.2% in 2026. Memory capital expenditure is expected to reach $80.4 billion in 2027, but the bank says long lead times will prevent new capacity from closing the 2027 gap. Omdia data showing record semiconductor revenue and four consecutive quarters of double-digit growth support the bullish memory outlook. Citi named Samsung Electronics, SK Hynix, Micron, SanDisk and Kioxia as top memory picks, and identified Applied Materials, Lam Research, Montage, TES, Eugene Technology and Techwing among equipment and materials beneficiaries. Micron's September 30 results and a potential labor dispute at its Taiwan operations are the next industry indicators, although no strike or production disruption has been declared.