The speculative appetite of small investors like Mr. Sanchez may seem at odds with an economy still reeling from a pandemic that has killed more than half a million Americans, decimated jobs and snuffed out businesses and livelihoods. But one of the biggest tools deployed by the U.S. government to cushion the economic blow — stimulus payments — is also driving a huge surge in investing by small traders.

Analysts at Deutsche Bank recently estimated that as much as $170 billion from the latest round of stimulus payments could flow into the stock market. They conducted a survey of retail traders in which respondents said they planned to put roughly 40 percent of any payment they received — or $2 of every $5 — into the stock market. Traders between the ages of 25 and 34 said they expected to put half of their stimulus check into stocks.

“That could lead to a bit more mania, speculation in the market,” said Patrick Fruzzetti, managing director and partner at Hightower Advisors, an investment firm. The “stimmies,” he said — using a popular online term for stimulus checks — will go into people’s trading accounts, and “they will trade.”