<![CDATA[Illegal wildlife trade is a major cause of both biodiversity loss and economic losses, especially in Indonesia. The siamang (Symphalangus syndactylus), an endangered, legally protected primate, is often illegally traded as a pet. This study aims to estimate the economic value of the siamang using the market price method and the captive rearing cost method, to qualitatively compare the practicality and methodological complexity of both methods, and to evaluate the potential of economic valuation as a reference for determining proportionate sentencing for wildlife crime offenders in Indonesia. Data were collected from October 2024 to January 2025 through online market monitoring across 23 Facebook trading groups—which identified 25 sale posts from 11 seller accounts—semi-structured interviews with four key informants, and field observations at Taman Safari Indonesia, as well as an analysis of 15 court rulings from the Directory of Decisions of the Supreme Court of the Republic of Indonesia. The results of the analysis indicate that the estimated economic value of the siamang is approximately IDR 13 million, with both valuation methods yielding comparable values. The market price method offers a more practical estimation approach, simpler data requirements, and a more accurate reflection of actual market dynamics. Analysis of court rulings found that fine amounts were inconsistent and generally lower than the estimated economic value of the species, indicating that sentencing determinations are not based on a standardized, science-based approach. The economic reference value generated in this study can support the development of a more proportionate sentencing framework in the future and contribute to more evidence-based wildlife conservation policy in Indonesia.]]>
