The global rental sector is undervalued by more than $1 trillion, according to research firm Morgan Stanley.

The research firm said it had compiled a list of the 50 most valuable car rental firms around the world and said the median valuations of the companies stood at $1,000 per share.

Morgan Stanley said its research showed that the median valuation of the firms in 2018 was $1.2 trillion, up 7 per cent from 2017.

Car rental firms are a diverse group of companies that range from car rental shops, luxury car rental chains and car rental services to car rental websites, car rental car parks and car leasing companies.

The research said there were over 1,500 rental car companies in the world, with many more in the pipeline.

Car rental companies typically rent vehicles at a discount, with a monthly fee of between $100 and $400 and a monthly maintenance fee of $5 or less.