President Joe Biden's $1.9 trillion stimulus will start flooding into the US economy soon, and some analysts say much of that money could end up invested in stocks or even bitcoin.

Over the weekend, the government began sending the $1,400 direct payments that will go to nearly everyone in the United States.

About $400 billion in payments will flow directly to households, going to individuals earning less than $75,000 a year or married couples making up to $150,000, as well as their children.

And that does not count child tax credits or unemployment benefits in the massive package, which also includes funds to contain Covid-19, accelerate vaccinations, help reopen schools and aid businesses and state and local governments.

The direct payments amount to $5,600 -- tax free -- for a typical family of four, funds officials hope will boost the US economy.

But the majority of Americans say that rather than spend, they will use the money to pay off debts, add to savings or to invest, according to one survey by Bank of America, which interviewed 3,000 people.

The bank found that 30 percent will use the money to repay their debt, 25 percent will save it and nine percent will invest.

Those funds will "stay within the financial system and don't create demand for goods and services in the real economy," the report found.

With only 36 percent saying they intend to spend these checks, "it's not clear who will be doing all the sustained, voracious consumption markets now are pricing in."

Major stock indices have hit new records two days in a row after Biden signed the stimulus measure into law last week, as investors are betting the rush of funds will spur a rapid recovery of the world's largest economy.

The bitcoin attraction

Mizuho Securities found that about 10 percent of the stimulus, or about $40 billion, will be invested in equities or in cryptocurrency such as bitcoin.

A survey of 235 people making less than $150,000 found that 35 to 40 percent of respondents said they would invest part of their stimulus checks in stocks and cryptocurrency.

And 61 percent of these investors intend to buy bitcoin, said Dan Dolev, one of the leaders of the Mizuho study.

"We were very surprised" that bitcoin "is a bigger investment vehicle than stocks," he said on CNBC.

The cryptocurrency hit an all-time high on Saturday at $60,000.

Another survey of 430 people by Deutsche Bank found that "survey respondents plan to put a large chunk (37 percent) of any forthcoming stimulus directly into equities," which it called "a sizable inflow" into the stock market.

In two prior rounds of stimulus checks in 2020 as the coronavirus pandemic brought the economy to a screeching halt, only about eight percent of the funds went into stocks, the bank said.

The survey showed that young people, aged 25 to 34, account for the biggest share of people planning to play the markets with their stimulus money, followed by those aged 35 to 44.

Goldman Sachs estimated that with the Biden plan, "households will represent the largest source of demand for US stocks in 2021."

Goldman Sachs economist David Kostin said the bank estimates household demand for equities this year will jump to $350 billion from $100 billion, "which reflects faster economic growth and higher interest rates than we had assumed previously, additional stimulus payments to individuals, and increased retail activity in early 2021."