the closest thing to [closed]
This is from an article by an investment journalist.
First, he gives statistics to show that this is a growth sector (faster than GDP). It is large(accounting for a tenth of GDP and employment). The sector is stable.
To summarise,, this is a safe investment, a safe place to put your money (always supposing you have any).
'A banker' is race-course slang for a sure bet. 'An industry banker' is a financial 'sure bet,' a safe investment.
Banker (LEXICO on-line dictionary)
2. British A supposedly certain bet. ‘the horse should be a banker for him in the Members' race’