Wall Street’s top regulators believe financial markets held up under the strain of the trading frenzy that drove shares of GameStop and other neglected companies to nosebleed-high prices last week. But they are assembling a timeline of events and reviewing whether investors got a fair shake, the Treasury Department said in a statement.

Treasury Secretary Janet Yellen convened a meeting Thursday of the financial sector’s Washington minders to discuss how an army of day-traders organizing through online message boards set off wild swings in some stocks.

The development sent shock waves through Wall Street, as the amateur investors squeezed billions of dollars in losses from hedge funds that had bet the stocks they targeted would drop. It also raised questions about the sturdiness of the infrastructure underlying financial markets and the fairness of ties among some of its gatekeepers.

Yellen, newly installed in a post that gives her a key coordinating role among regulators, huddled with the heads of the Securities and Exchange Commission, the Federal Reserve, the New York Fed, and the Commodity Futures Trading Commission.

“The regulators believe the core infrastructure was resilient during high volatility and heavy trading volume and agree on the importance of the SEC releasing a timely study of the events,” the Treasury statement released Thursday evening said. “Further, the SEC and CFTC are reviewing whether trading practices are consistent with investor protection and fair and efficient markets.”

In a Thursday morning interview on ABC’s “Good Morning America,” Yellen said regulators “need to understand deeply what happened before we go to action. But certainly we’re looking carefully at these events.”

Amateur investors, many gathering on the subreddit r/WallStreetBets and trading through commission-free platforms such as Robinhood, transfixed the financial world and beyond last week by buying up GameStop shares, pushing the price of the video game retailer’s stock past $480. The otherwise marginal video-game retailer’s stock started the year trading at around $17 — and it has dropped precipitously since last week’s action, cratering another 42 percent on Thursday to close at $53.50.

Other “meme stocks” caught up in the retail trading craze likewise have collapsed in recent days. Shares of AMC Entertainment, which started the year below $2 and spiked above $20 last week, dropped 21 percent Thursday to close just above $7. Bed Bath & Beyond stock has shed roughly half its value since hitting a high near $54 last week.

Advocates of stricter financial industry oversight have identified a number of areas of potential concern highlighted by the recent turmoil. Regulators and lawmakers are primed to probe several, including online trading platforms selling their customers’ orders to giant Wall Street firms — a practice known as payments for order flow — and whether hedge funds should disclose more about their investment positions.

The SEC already is combing through social media and message boards for evidence of potential market manipulation in the chatter among retail traders, Bloomberg News reported this week. But experts in securities law say it could be difficult to find illegal conduct.

"To the extent people are open and transparent about why they are trading, it is hard to think of that as deceptive in the traditional sense of market manipulation,” said Robert Cohen, a partner at Davis Polk and a former SEC enforcement lawyer.

"Volatility is a natural part of markets,” he added. “What is important is that markets have shown they have the infrastructure and resilience to handle it... I don’t know that you can regulate volatility out of the market.”