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: Comparative Analysis of Optimal Portfolio Using Markowitz Model and Single Index Model Based on Value at Risk (VaR)
Abstrak: Investasi merupakan salah satu variabel penentu dan berpengaruh positif terhadap pertumbuhan ekonomi (PDB). Berinvestasi pada saham dengan kapitalisasi pasar besar akan meningkatkan pertumbuhan IHSG. IDX80 merupakan indeks yang terdiri dari 80 saham yang memiliki likuiditas tinggi, kapitalisasi pasar besar, dan fundamental perusahaan yang baik. Penelitian ini bertujuan untuk mencari kombinasi saham yang memenuhi kriteria dalam pembentukan portofolio optimal berdasarkan model Markowitz dan Single Index Model serta mencari kinerja portofolio optimal terbaik menggunakan Value at Risk. Penelitian ini menggunakan data harga saham bulanan, IHSG, dan suku bunga acuan BI7DRR periode Februari 2019–Februari 2022. Hasil penelitian menunjukan bahwa terdapat 17 kombinasi saham yang membentuk portofolio optimal Single Index Model dengan expected return sebesar 0,01882 dan nilai varian sebesar 0,002582 perbulan. Sedangkan portofolio optimal yang terbentuk dengan model Markowitz menghasilkan enam kombinasi saham, expected return dan varian masing-masing sebesar 0,002243 dan 0,003866 per bulan. Berdasarkan hasil perbandingan menggunakan Value at Risk, portofolio optimal menggunakan metode Single Index Model lebih baik dibandingkan dengan model Markowitz karena memiliki expected return tertinggi, varian terbaik, kemungkinan kerugian terendah, dan kinerja portofolio terbaik., Investment is one of the determining variables and has a positive effect on economic growth (GDP). Investing in stocks with large market capitalization will increase JKSE growth. IDX80 is an index consisting of 80 stocks that have high liquidity, large market capitalization, and good company fundamentals. This study aims to find a combination of stocks that meet the criteria in forming an optimal portfolio based on the Markowitz model and the Single Index Model also to find the best portfolio performance using Value at Risk. This study uses reports of monthly stock price, JKSE, and interest rates BI7DRR period February 2019– February 2022. The results show there are 17 stocks combination form the optimal portfolio of the Single Index Model with an expected return of 0,01882 and a variance value of 0,002582 per month. While the optimal portfolio formed by the Markowitz model produces six stocks combination, the expected return and variance are 0,002243 and 0,003866 per month, respectively. Based on comparison using Value at Risk, the optimal portfolio by the Single Index Model is better than the Markowitz model because it has the highest expected return, the best risk, the lowest possible loss, and the best portfolio performance.
Keyword: Single Index Model, Value at Risk (VaR), IDX80 Index, Optimal Portofolio, Markowitz Model

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