With investors growing more nervous by the day about elevated inflation and the economy, September turned out to be extremely challenging for a long list of industries and stocks, including some of the market most loved names. 

The Nasdaq Composite plummeted 10.5%, the Dow Jones slumped 8.8%, while the S&P 500 shed 9.3% across the course of the month. On the back of the result, Wall Street recorded its third straight quarter of negative returns, something that hasn't occurred since the Global Financial Crisis back in 2008.

Tech stocks have long been a favourite in the Selfwealth community, but with the sector under pressure last month, what were members buying and selling?

US share trading activity

As we foreshadowed in our August report, there was plenty of action in the ETF energy space last month, with the ProShares Ultra Bloomberg Natural Gas (NYSE: BOIL) making a dramatic reappearance among the most traded stocks, and the ProShares Ultra Bloomberg Crude Oil ETF (NYSE: UCO) making its debut inside the top 20. 

Those moves came in response to volatile energy prices, with natural gas surging in response to supply cuts hitting Europe, and oil prices easing towards their lowest levels since the start of the year as concerns grow about the state of the economic outlook.

BOIL was the fifth most traded security in September, while UCO finished the month in ninth position, both of which indicate strong opinions regarding energy prices. With coal producer Peabody Energy Corporation (NYSE: BTU) also joining the action, it is clear that energy is one of the pressing trading themes at this time while the northern hemisphere hurtles towards a potentially bleak winter, and the global energy mix remains at the mercy of the war in Ukraine.Affirm (NASDAQ: AFRM) was a surprise sighting on the leaderboards, with the buy-now pay-later stock well and truly on the outer, falling around 20% throughout September, but also nearly 90% off its all-time highs. However, it appears the majority of last month trading in the stock was driven by sell orders, and some traders hoping to pick up a rebound trade.Elsewhere, the biotech sector also gained visibility last month in the midst of the market sell-off, with the Direxion Daily S&P Biotech Bear 3X Shares ETF (NYSE: LABD) the 11th most actively traded US stock in September, and Immunitybio (NASDAQ: IBRX) slightly behind in 17th position. The latter was one of the best performing momentum stocks over the month, with its market cap increasing by nearly one-quarter, and each swing encouraging new traders to follow the money.Top 20 stocks traded by valueCode SecurityBuy-sell Ratio1SQQQProShares UltraPro Short QQQ ETF50.0%2TQQQProShares UltraPro QQQ51.1%3AAPLApple50.2%4TSLATesla58.9%5BOILProShares Ultra Bloomberg Natural Gas53.1%6AMDAdvanced Micro Devices54.8%7MSFTMicrosoft53.9%8BACBank of America50.7%9UCOProShares Ultra Bloomberg Crude Oil ETF50.5%10CCitibank50.0%11LABDDirexion Daily S&P Biotech Bear 3X Shares50.3%12WFCWells Fargo49.0%13AFRMAffirm45.8%14JPMJPMorgan48.1%15NIONio49.5%16GOOGLAlphabet72.7%17IBRXImmunitybio50.0%18BTUPeabody Energy Corporation47.5%19NVDANvidia71.2%20UVXYProShares Ultra VIX Short Term Futures ETF49.4%

Which US shares are the most held?

Even though Tesla (NASDAQ: TSLA) shares were under pressure last month, falling 3.8% across September, the stock remained atop the list of the most held US stocks on the Selfwealth platform. Tellingly, the value of all holdings in TSLA was broadly in line with the month prior, suggesting strong conviction among long-term holders, and money flow from new investors effectively offset the underlying decline in the company share price.One stock that is no longer featuring quite as prominently in the spotlight as it once did is GameStop (NYSE: GME), which although still popular, now finds itself down in eighth position, the lowest recorded ranking for the stock in the Selfwealth community. Last month saw the collective value of all holdings in GME slump 15%, sparked by poor sentiment across the market.Some stocks with solid downtrends in September are still sitting high in the community charts, with names like Microsoft (NASDAQ: MSFT), Alphabet (NASDAQ: GOOGL), Meta (NASDAQ: META), and Nvidia (NASDAQ: NVDA) all a common sight in the portfolios of many Selfwealth members. However, each of these names hit a year-plus low in September, with tech stocks proving to be the most susceptible to the latest leg in the market downturn.Shares in PayPal (NASDAQ: PYPL) were lower by about 8% last month, but enthusiasm for the digital payments company continues to build in the Selfwealth community, with the stock rising one place to 17th position. It would appear a number of investors have been buying the tech name in the hope of a long-term recovery playing out, which prior to September, was looking like a distinct prospect after the company provided an encouraging earnings report at the start of August.And lastly, making its way back into the top 20 for the first time since June is Toronto-Dominion Bank (NYSE: TD). The Canadian financial joins its peer in the Royal Bank of Canada (NYSE: RY), highlighting that the trend that caught on earlier this year was no short-term flutter, instead it appears to be a targeted theme as central banks across the US and Canada hike rates aggressively.US StockCompany1TSLATesla2AAPLApple3RYRoyal Bank of Canada4MSFTMicrosoft5GOOGLAlphabet6AMZNAmazon7BRKBerkshire Hathaway8GMEGameStop9BABAAlibaba10VOOVanguard 500 Index Fund ETF11METAMeta Platforms12ENBEnbridge13NVDANvidia14ARKKARK Innovation ETF15PLTRPalantir16BCEBCE17PYPLPayPal18DISWalt Disney19AMDAdvanced Micro Devices20TDToronto-Dominion Bank

That all for this Trade Trends report, stay tuned for the next edition this time next month!