Why did the NEP end?

The New Economic Policy (NEP) in the Soviet Union ended primarily due to growing concerns among Bolshevik leaders about the resurgence of capitalism and the influence of the kulaks (wealthier peasants). By the late 1920s, Joseph Stalin and other party officials believed that a more centralized, state-controlled economy was necessary to achieve rapid industrialization and collectivization. This shift was driven by a desire to strengthen the socialist state and eliminate perceived threats to communist ideology. Consequently, the NEP was abandoned in favor of the first Five-Year Plan in 1928, marking a significant transition in Soviet economic policy.