Judul: The Effect of Financial and Macroeconomic Performance on Stock Returns Before and During Covid-19 (Case Study of Animal Feed Companies on the Indonesia Stock Exchange)
Abstrak: Investment activity is one of the activities that can encourage economic growth. Investments can be made in the real sector and the financial sector. The livestock industry has good prospects in Indonesia to meet people's needs for animal protein. The animal feed companies with the largest production in Indonesia sequentially are PT. Charoen Pokphand Tbk (CPIN), followed by PT. Japfa Comfeed Indonesia Tbk (JPFA), PT Malindo Feedmill Tbk (MAIN), and PT. Sreeya Sewu Indonesia Tbk (SIPD), where the four companies were open and affected by Covid-19 which resulted in changes in their financial and share performance. On the other hand, there are movements in external factors (corn prices, soybean prices and the exchange rate are thought to be factors that play a role in the company's performance. This study aims to determine the company's financial performance, the impact of changes in external factors on stock returns, the relationship between internal and external factors on stock return performance The scope of this research is animal feed sub-sector companies listed on the Indonesia Stock Exchange in the period before and after Covid-19, namely from 2017 to 2021. The independent variables used in this study are Cash Ratio (CashR), Debt Equity Ratio (DER), Net Profit Margin (NPM), Inventory Turnover (ITO), exchange rates (exchange rates), international soybean prices, and local corn prices. While the dependent variable in this study is the stock price of animal feed companies. The analytical method used for this research is 1) panel data regression, 2) different test and 3) moderation regression. The results of the study show that the movement of the performance of the 4 companies fluctuated during the study period, especially at the beginning of the Covid period. The stock movement that occurs from the pattern shows that the exchange rates at the two companies (JPFA and MAIN) need to be considered because they provide different patterns. testing of internal and external factors with stock returns obtained some evidence of a significant relationship, namely NPM, CashR and DER while testing for moderation obtained two outputs that had a significant impact, namely NPM*LnKurs and CashR*LnKurs. There is a special note that NPM has different results before and during covid. Companies can still improve performance in general with the help of solvency. Where with solvability the company will have a cheaper cost of capital and efforts to increase business capacity are greater.
Keyword: Covid-19, External Factor, Feed Company, Internal Factor, Stock Return.

Judul: The Impact of Working Capital Turnover and Macroeconomic Factors on The Profitability of Agribusiness Companies on The Indonesian Stock Exchange
Abstrak: Modal kerja merupakan bagian dari pembiayaan. Terjadinya pandemi Covid 19 di tahun 2020 memberikan disrupsi pada perusahaan sektor agribisnis yang sudah go public. Namun, perusahaan tetap dituntut oleh investor untuk selalu berusaha untuk memperoleh keuntungan. Profitabilitas selain ditentukan oleh pengelolaan perputaran modal kerja juga ditentukan oleh kondisi eksternal terutama faktor mekroekonomi, serta juga jenis sektor dari sektor perusahaan agribisnis. Oleh karena itu, tujuan dari penelitian ini adalah menganalisis pengaruh perputaran modal kerja dan variabel makroekonomi terhadap profitabilitas sebelum dan saat pandemi pada perusahaan agribisnis on-farm dan manufaktur. Data yang digunakan adalah data laporan keuangan perusahaan yang sudah tercatat di Bursa Efek Indonesia. Metode analisis yang digunakan yaitu analisis regresi data panel dari tahun 2017 kuartal satu sampai dengan 2021 kuartal empat. Hasil estimasi menunjukkan bahwa profitabilitas perusahaan agribisnis sektor on-farm dipengaruhi signifikan oleh perputaran persediaan, suku bunga, dan adanya pandemi. Profitabilitas perusahaan agribisnis sektor manufaktur dipengaruhi signifikan oleh perputaran piutang dan persediaan., Working capital is part of financing. The Covid-19 pandemic in 2020 disrupted agribusiness sector companies that had gone public. However, investors still require companies to strive to make a profit. Apart from being determined by the management of working capital turnover, profitability is also determined by external conditions, especially macroeconomic factors, as well as the type of sector of the agribusiness company. Therefore, this research aims to analyze the influence of working capital turnover and macroeconomic variables on profitability before and during the pandemic in on-farm agribusiness and manufacturing companies. The data used in this research are companies financial report listed on the Indonesia Stock Exchange. The analysis method used is panel data regression analysis from 2017 quarter one to 2021 quarter four. The estimation results show that inventory turnover, interest rates, and the presence of a pandemic significantly influence the profitability of on-farm sector of agribusiness companies. Receivables and inventory turnover significantly influence the profitability of manufacturing sector of agribusiness companies.
Keyword: disrupsi, manufaktur, modal kerja, on-farm, profitabilitas

Judul: Formulasi Hamiltonian untuk Menggambarkan Gerak Gelombang Soliter Dimensi Tiga di Permukaan Laut
Abstrak: Gelombang permukaan adalah gelombang yang terjadi perbedaan rapat massa antara air dan udara. Salah satu gelombang permukaan yang ditinjau adalah gelombang soliter. Formulasi gelombang soliter dilakukan dengan menggunakan formulasi Hamiltonian.
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