Studying the relationship between working capital and cash flow affecting profitability of Vietnamese securities companies, through tobit model presented in the form of two-dimensional panel data: time dimension (from 2012 to 2019), the space dimension is the enterprise (48 securities companies), corresponding to 370 observations, using STATA 14 software to verify and estimate the tobit model. As a result, the relationship between working capital and cash flow (available cash flow) significantly affects the profitability of Vietnamese securities companies, Average collection period (ACP) has a negative relationship with ROE/ROA, while Average Payout Period (APP) has no significant effect on ROE/ROA. The implication is that securities companies can increase the profitability of the business by shortening the cash conversion cycle, shortening the receivable collection period, that is, for securities companies with positive cash flows, investment should be reduced. working capital to increase profitability.

A linear regression model supplied in the form of two-dimensional array data was used to investigate the factors affecting the short-term solvency of Vietnamese securities companies. The data is examined with 48 securities companies from 2012 to 2019. The study employed STATA 14 software to evaluate and select regression models, test, and estimate regression models using array data from 235 observations. The findings revealed four characteristics that influence the short-term solvency of securities businesses in Vietnam: the size of the securities company and the quick ratio have a positive impact. In contrast, the debt ratio and the working capital turnover period have a negative effect.

The goal of creating, forming, and developing businesses in general and securities companies in particular, whose ultimate goal is profit, high and stable profitability is the goal of any company. However, due to their specific business lines, securities companies are affected by risks such as market risk (which is the value corresponding to the level of loss that may occur when the market price of assets currently owned and expected to be owned under the underwriting commitment fluctuates in an adverse direction); Payment risk (is the value corresponding to the level of loss that may occur when the counterparty is unable to make payment on time or deliver assets on time as committed; operational risk (is the value corresponding to the level of losses that may occur due to technical errors, system and business process errors, human errors in the operation process, due to lack of business capital arising from expenses and losses from investment activities, due to other objective reasons). The problem is how the securities company can balance the safety goal, limit the possible risks and at the same time still increase the ability of the enterprise profitability. In practice, there are many methods to measure risk, but one of the most widely accepted methods of predicting risk and bankruptcy today is Z-score of the US economist's - Edward I. Altman – a lecturer of New York University faculty member set. In the US, about 95% of bankruptcies are forecast from the Z-score one year before the closing date, but this rate drops to just 74% for 2-year forecasts. From the initial Z-index forecast, Professor Edward I. Altman has developed it into Z' and Z'' to be applicable to each type and industry of the business. The Z'' coefficient is similar to the S&P credit rating.

Capital structure is understood as the proportion of each source of capital in the total capital that the business, or the combination of debt and equity that the company uses for business operations. The decision on capital structure is one of the important financial decisions for any business, reducing capital costs and eliminate unwanted risks. In other words, a reasonable structure is the balance between risk and profit, from which enterprises can implement their business strategies. In fact, the capital structure of each enterprise depends on many factors such as the macro conditions of each country, each industry in which the enterprise operates, or the individual characteristics of each enterprise, etc., so there is no single structure common to all businesses. Therefore, the study of capital structure is a topic that is always interested by scientists at different stages, as well as business managers to make effective selection decisions.