The A.I. boom has led to a surge for semiconductor stocks that some on Wall Street are worried has gone too far, and some traders are using leveraged funds to bet that a reversal is coming soon. Over the past month, shares of A.I. leader Nvidia have jumped 41%, while the Philadelphia Semiconductor Index has gained 17%. NYU finance professor Aswath Damodaran told CNBC on Thursday that he sold half of his Nvidia stake because its dramatic rise made it hard to hold onto as a value investor. Some traders are making more aggressive bets that the run has gone too far. The Direxion Daily Semiconductor Bear 3x Shares ETF (SOXS) was one of the top 10 ETFs for inflows over the past week, pulling in more than $400 million, according to FactSet. The interest comes despite the fund being down about 70% year to date. Meanwhile, more than $500 million were pulled out of the Direxion’s Daily Semiconductor Bull 3x Shares ETF (SOXL) , the fourth-most outflows over the past week. The FactSet flow data is through Thursday. These funds are often volatile and not designed to be long-term holdings, instead serving as short-term bets. They also have high expense ratios relative to most other ETFs. “These leveraged ETFs seek a return that is 300% or -300% of the return of their benchmark index for a single day,” Direxion’s website says. “The funds should not be expected to provide three times or negative three times the return of the benchmark’s cumulative return for periods greater than a day .” As a result, their flows can reverse quickly and are not necessarily a good measure of long-term outlook for chip stocks. The VanEck Semiconductor ETF (SMH) , which would be better suited to long-term investors, saw inflows of less than $40 million this week, a slowdown from prior weeks. Here are the top five ETFs by inflows over the past week. Here are some other notable fund flow data points from the week. The Vanguard Tax-Exempt Bond ETF (VTEB) brought in more than $280 million, suggesting that MUB’s inclusion on the top five could be part of a broader shift into municipal bonds. The iShares Russell 2000 ETF (IWM) had the most outflows, shedding more than $785 million. That reversed much of a large inflow from the previous week .