Why float on a stock exchange when you can raise the money privately? It used to be the case that companies would have to go public to raise a significant amount of capital (usually more than $100 million). These days, start-ups can do this privately.

Dublin loan start-up Future Finance raised €150 million in private funding to grow its student loan platform. In the US , Airbnb raised $100 million in funding last November, only months after closing a $1.5 billion mega-round, while Snapchat raised $537 million in a single capital funding round.

In 1997, ecommerce retailer Amazon went public at a market capitalisation of about $440 million, just two years after its first round of institutional financing. Compare that with Uber, which is still private six years on and has a valuation of more than $50 billion, after raising more than $10 billion in funding.

The stats also show that during the first half of 2015, $38.8 billion was raised through "private IPOs" compared to $3.5 billion in public offerings. When you consider all the costs associated with an IPO, it would seem a private IPO is often the best way forward. Private companies aren't subject to quarterly assessments of performance either. Furthermore, when you are a publicly listed company, the stock exchange expect things to be done in a certain way, as Mike Ashley of Sports Direct (above) learned this week.

He spoke to the media about its trading problems, rather than issuing a proper statement to the stock exchange.