Step 1: Decode the acronym SPREE.
SPREE stands for Scheme for Promotion of Registration of Employers and Employees. It aims to bring informal and unorganized sector workers under a formal social security umbrella.
Step 2: Identify the launching organization.
ESIC (Employees' State Insurance Corporation) launched SPREE 2025. ESIC functions under the Ministry of Labour and Employment to provide health insurance and social security to workers.
Step 3: Eliminate the distractors.
RBI handles monetary policy, SEBI regulates securities markets, and NITI Aayog is a policy think-tank. Employee insurance registration is exclusively ESIC's domain.
\[ \boxed{\text{ESIC}} \]