Listed Companies' Differences In Profitability Of The Transportation Industry In China

Today transportation industry is playing a pivotal role in social development.The profits of transportation enterprises are direct reflections of the industry's overall situation.Profitability has always been an essential research topic for many scholars at home and abroad,while a wide array of studies only remain in the stage of using general multivariate regression analysis and further discussion is still inadequate.As an effective statistical tool for nested data structure,hierarchical linear model(HLM),integrating the individual effects with the background effects,defines submodels of different levels to demonstrate the variation of profit rates with withingroup variation and between-group variation,which is more persuasive.In the paper the transportation industry is classified in terms of the modes and logistics activities.We select 96 listed companies and 6 sub-professions in the industry as our research objects,establish the twolevel linear model where company variables are considered as the first level and sub-profession variables as the second level,and determine the final model through the process of introducing variables step by step,testing the data reasonableness and analyzing the results.It is shown that company's main business cost and total assets turnover both have certain effects on profit rates,the variation of which,meanwhile,can also be illustrated by sub-profession's stability and business income.The differences among sub-professions,among which,in addition,the final model fits best to the air transport industry,will make a direct impact on profits.