Stock market investing in Britain is mainly done by professionals like fund managers, folk that ordinary people trust with their money because pros understand investing better than they do. It's the same way in the US, although Americans are more likely than Brits to maintain a small portfolio of stocks they have a personal interest in.
But in China, millions of ordinary citizens have accounts to buy company stock directly - and that's causing big problems for the government now that markets are nosediving.
There are an estimated 90 million "retail" investors in China - normal folk who own shares. Credit Suisse reckons an incredible 80% of urban Chinese households have invested in equity, putting around 30% of their collective cash into stocks.
Credit Suisse has a great chart that puts in context just how huge all of this exposure is. The bank says there are around 258 million stock trading accounts open on the Shanghai and Shenzhen exchanges, the two major ones. A high proportion of those likely to be retail investors, with a third of the total opened in just the last nine months.
As you can see below, that dwarfs the population of most Asian countries and is over 80% of the entire US population.
Credit Suisse
Credit Suisse's graph of stock trading accounts in China against populations.
China's huge retail investor base both explains why stock markets are crashing right now and why the Chinese government is taking such extraordinary measures to try and stop the fall.
Ordinary people have borrowed more money than they have to buy shares. A dip in prices has led to lenders asking for more cash to cover losses. That's forcing retail investors to sell shares to raise cash and the rush of sellers is pushing down prices.
As for why the government is so worried, it obviously doesn't want millions of belligerent Chinese who are angry about losing money. Credit Suisse warned this week that the crisis could soon risk "social stability" in the country if it isn't resolved quickly. CS analyst Dong Tao says that "some homeowners mortgaged their house to invest in stocks."
And the collapse is showing up the government. Here's Credit Suisse: "The market weakness also undermines President Xi Jinping's reform plans and anti-corruption campaign. Premier Li Keqiang expressed his strong preference for having "one big shot" at stopping the panic after he returned from a European trip."
That "one big shot" has turned into several big shots, after initial attempts failed to do much to stem losses.