Jay Clayton, chairman of the SEC.

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The chairman of the Securities and Exchange Commission, Jay Clayton, said on Thursday that he is concerned that individual investors are deploying money for risky, short-term trades and causing the price of certain stocks to skyrocket.

Clayton’s comments came in response to a question from CNBC’s Andrew Ross Sorkin, who asked the regulator if eye-popping rallies in stocks including Tesla are cause for alarm.

“Here at the SEC, when we think about that investor, we think about someone who’s investing for the long term: Investing over time, doing it on a monthly basis,” Clayton said. “What we are seeing is significant inflows from retail investors and they have the hallmarks of short-term inflows. And does that concern me? Sure.”

“Because that’s more trading than investing,” he continued. “Short-term trading is much more risky than long-term investing, and so I do worry.”

Though the SEC boss didn’t mention the electric car maker by name, the meteoric rise in Tesla’s equity over the last year has left analysts and investors wary that the price reflects more emotion than business fundamentals.

Tesla, which posted its fourth straight quarter of profits on Wednesday, is now worth more than Ford and General Motors combined while delivering just a fraction of the volume of automobiles. Elon Musk’s carmaker is now worth about $300 billion, the result of a 512% increase in its stock price over the last 12 months.

Though some analysts have argued that Tesla’s newfound valuation may reflect a long-term belief that the company will lead a broader, nationwide shift to electric cars, others have decried the spike as reckless.

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JMP Securities, for example, downgraded Tesla equity on Tuesday ahead of earnings and wrote that “we cannot arrive at a reasonable basis for arguing that the stock should be valued above current levels, even considering our fundamental outlook.”

Morgan Stanley’s widely followed autos analyst, Adam Jonas, noted last week that “the power of hope” is taking an ever-more-important role in its climb.

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