Judul: Optimal Portfolio Through Single Index Model Based on Value at Risk and Expected Shortfall
Abstrak: Peningkatan jumlah investor pasar modal pada tahun 2021 ternyata tidak diikuti dengan adanya peningkatan tingkat literasi keuangan di pasar modal. Saham merupakan satu instrumen yang diminati investor dalam pasar modal karena dapat memberikan return yang tinggi, namun tentunya dalam berinvestasi di saham investor perlu memiliki strategi untuk mengurangi risiko kerugian. Penelitian ini bertujuan untuk membentuk portofolio optimal pada sektor energi dengan pendekatan Single Index Model beserta pengukur risiko kerugiannya menggunakan pendekatan Value at Risk dan Expected Shortfall . Data yang digunakan pada penelitian ini berupa data harga saham, IHSG dan suku bunga acuan BI-7DRR bulanan periode Februari 2021-Februari 2023.Hasil penelitian menunjukkan terdapat 8 kombinasi saham yang membentuk portofolio optimal diantaranya, yaitu AKRA, BSSR, ENRG, HRUM, ITMG, MBSS, PTRO dan PSSI dengan nilai expected return portofolionya sebesar 5,87% dan risiko sebesar 12,76%. Berdasarkan perhitungan risiko kerugian melalui pendekatan VaR diperoleh kerugian maksimum portofolio selama 1 bulan sebesar 34,92655%, 26,40668%, 21,86477%, sedangkan melalui pendekatan ES sebesar 39,16297%, 31,63065%, 27,78349% pada tingkat kepercayaan yang berbeda secara berturut-turut sebesar 99%, 95% dan 90%., Increasing in the number of investors in the capital market in 2021 has not been followed by an increase in financial literacy in the capital market. Stocks are an instrument that investors are interested in the capital market because they can provide high returns, but in investing in stocks, investors need to have strategy to mitigate the risk of lossses. This study aims to form an optimal portfolio in the energy sector using the Single Index Model approach along with measuring the risk of loss using the Value at Risk and Expected Shortfall approaches. The data used in this study are stock price data, IHSG and the monthly BI-7DRR for the period February 2021-February 2023. The results of the study show that there are 8 combinations of stocks that form the optimal portfolio, including AKRA, BSSR, ENRG, HRUM, ITMG, MBSS, PTRO and PSSI with an expected portfolio return value of 5,87% and a risk of 12,76%. Based on the calculation of the risk of loss through the VaR approach, the maximum portfolio loss for 1 month is 34,92655%, 26,40668%, 21,86477%, while through the ES approach it is 39,16297%, 31,63065%, 27,78349% in different confidence levels respectively by 99%, 95% and 90%.
Keyword: energy sector, expected shortfall, optimal portfolio, single index model, value at risk

Judul: Investment Risk Estimation with Monte Carlo Simulation Method on Renewable Energy Sector Stock Portfolio
Abstrak: Analisis risiko penting dalam kegiatan investasi saham, terutama di sektorsektor potensial seperti energi terbarukan. Value at Risk (VaR) dan Expected Shortfall (ES) adalah ukuran untuk menunjukkan tingkat risiko. Penelitian ini bertujuan untuk mengestimasi VaR dan ES menggunakan simulasi Monte Carlo berdasarkan data harga saham harian mulai tanggal 1 April 2020 sampai dengan 31 Maret 2021. Pengukuran VaR dan ES pada portofolio yang dibentuk dengan metode Mean-Variance Efficient Portfolio menunjukkan nilai yang lebih kecil daripada saham tunggal. Komposisi saham tersebut terdiri dari FSLR 64,35%, REGI 27,96%, dan SEDG 7,69%. Uji validitas model estimasi VaR dilakukan dengan menggunakan metode Kupiec Test. Hasil pengujian validitas menunjukkan bahwa nilai VaR portofolio dengan simulasi Monte Carlo akurat untuk mengestimasi tingkat risiko suatu investasi.
Keyword: Expected Shortfall, Monte Carlo simulation, Value at Risk

Judul: Morfologi Organ Reproduksi Betina Walet Linchi (Collocalia linchi)
Abstrak: This research is aimed to describe the morphology of the female reproductive organs of the cave swiftlets (C. linchi ) macroscopic and microscopically. Four female reproduction organs were used in this study. Microscopic observation was done using Hematoxilin – eosin (HE), alcian blue (AB) pH 2.5 and periodic acid Schiff (PAS) staining methods. The reproductive organs were consisted of ovarium and oviduct. The oviduct has five parts: infundibulum, magnum, isthmus, uterus and vagina. The mucosa of oviduct has mucosal folds and lined with columnar ciliated epithelial cells. Glandular glands were found in the lamina propria of oviduct, except in the vagina. The thick muscle of sphincter uterovagina was found in the border between uterus and vagina. Using AB-PAS staining methods, it was detected that oviduct contained neutral and acid carbohydrate, especially in the secrete glands of oviduct.
Keyword: oviduct., ovarium, Collocalia linchi