Very negative. It allows for zombie companies to survive for far longer than they ideally should have. So many companies in Japan that should have gone bankrupt years ago but are still surviving. Also makes everyone complacent and uncompetitive at global scale, which has been the theme for Japan for past few decades.
The government is not good at creating and sustaining businesses despite their nearly unlimited resources and centuries of attempts. When the government owns large stakes in businesses then the business operations become political, as the government is elected and the government owns the business, so the business is now answerable to voters. The business will be encouraged to make malinvestments in politically important projects and regions, allow unproductive employees to remain, and lead to general stagnation.
Some socialists have openly stated that the end goal of democratically run companies can be attained by funneling government money directly into buying equity stakes in businesses, growing over time. This would be an extremely terrible outcome for anyone that likes productivity and efficiency.