A year or two ago, there were warnings that a silicon valley "party" was coming to an end.

"Crazy money is drying up," one observer said.

This newspaper refers to the "increased caution" in venture capital circles.

The party may have ended, but then there was a more frenetic -- and perhaps more exclusive -- after-party.

In recent years, while the total amount of venture capital has remained broadly stable, there has been a lot of money flowing into start-ups that are already fully fledged.

A significant portion of that investment comes from the Vision Fund, a technology investment arm of Japan's Softbank.

It has raised $93bn, partly from softbank itself, but more from Saudi Arabia, ABU dhabi's sovereign wealth funds and companies such as Apple and Foxconn.

The fund raced to put the money into operation.

More than $4 billion has been invested in WeWork, a tech start-up in the real estate sector, which has given the latter an incredible high valuation.

The equivalent amount of money goes to Nvidia, the listed chipmaker, and Didi Chuxing, China's ride-hailing app.

The fund is planning a big investment in ride-hailing company Uber, which already has billions of dollars in cash.

It's not just a vision fund.

Slack, which develops office communications software, has just raised $250 million, valuing the company at more than $5 billion, despite the fact that the funds raised in the previous two rounds of funding have not been spent.

Pinterest, an Internet photo-sharing site, has raised its valuation to $12 billion.

Total investment in venture capital funds fell slightly in the second quarter of this year, but the $100 million or more "super round" fundraising attracted a 60 percent increase in investment, according to CB Insights.

Investors lined up to invest $600 million in Social Capital.

The "blank cheque" company promises to buy a tech start-up with the money.

Why do you have to do so when a startup can go public on its own?

The reason for this is that listing is a hassle, involving compliance, investor demonstrations and uncertainty, and often prices fluctuate after going public.

But Social Capital's investors are said to be taking a long-term view.

According to company documents, skipping the annoying disclosure of information and public scrutiny will make the whole process more "transparent", and the bizarre statement is almost speechless.

In short, money is being crammed into mature start-ups through non-public channels, like stuffing grain to a goose.

The question is whether the fattening of things has any advantage.

Such high valuations, and reckless spending, are a bubble.

Private investors seem to have concluded that we live in a world of low growth and perpetual low interest rates.

If so, it does make sense to pay high prices for companies that will beat the economy as a whole.

But historically, valuations -- not interest rates -- are a reliable guide to returns.

But let's say we're not in a bubble, and in a sense it's worse.

The public stock market used to be a rough guide to the economy.

Years of acquisitions, share buybacks and recent surges in private investment have made the stock market more untruthful about the economy.

The number of listed companies in the us is now half that of 20 years ago.

If one of the most dynamic companies increasingly clique of insiders, and on which most working people to increase savings investment dc plans, but could not, there will be bad consequences.

The reasonableness of American capitalism is that it has the benefit of the vast majority of americans, and that belief has no firm foundation.

If we were in a tech bubble and the bubble burst, the losers would be those who could afford to lose.

But if we are witnessing the gradual withdrawal of growth technology companies from the open market, the link between markets and democracy will be weakened.