When did American capitalists begin investing millions of dollars in Cuba's sugar cane plantations?

American capitalists began investing millions of dollars in Cuba's sugar cane plantations in the late 19th century, particularly after the Spanish-American War in 1898. The U.S. involvement in the war and subsequent political changes in Cuba opened up opportunities for American investors. By the early 20th century, American investments significantly increased, leading to substantial control over Cuba's sugar industry.