Hello, everyone, nice to be member of this group :-)

First of all, I would like to apologize in advance if I ask too basic questions, but working with panel data and Stata is completely new to me.

I have data for 550 companies for period 2009-2018 (since it is unbalanced panel, I have 4576 observations). I am trying to find appropriate model specification, so I conducted F test and BP test for individual effects, and they showed that individual effects are not statistically significant (both, fixed and random). Because of large N and small T dimension, I did F test for fixed time effects, that turned out to be statistically significant. I included them in model through time dummies and run the regression (OLS). I hope that all I have done is correctly :-)

Tests showed me that model has problem with heteroskedasticity and autocorrelation. But, what worries me more is the fact that residuals are not normally distributed (according to Shapiro-Wilk test). How can I deal with these problems?

I need to mention that I am trying to repeat existing model from literature in terms of model variables: dependent, independent.

Thank you all for reading. If someone can give me advice, I would be grateful.