After a record-breaking streak for the ASX, which saw 11 consecutive monthly gains in a row, September was a turning point, with the benchmark ASX 200 index sagging 2.7%.

Selling pressure came from overseas as rising Treasury yields in the US weighed on local investor sentiment. In addition, concerns about the prospect of financial contagion in relation to a possible default of Chinese property developer Evergrande also had investors heading for the exits. If that wasn't enough, plummeting iron ore prices also took their toll among the nation largest miners.

As risk-off became the prominent mantra, it was growth names that copped the brunt of the sell-off, with tech, materials and health stocks all falling sharply, offsetting a major re-rate in the energy sector as oil prices hit multi-year highs and uranium shares rallied.

Here is what the Selfwealth community were buying and selling across the ASX through their Selfwealth trading accounts during September.

Which shares and ETFs were the most held?

For the first time across the Selfwealth community, CSL (ASX: CSL) was dislodged atop the charts of the most-held stocks. With the health care sector struggling across the month of September, largely on the back of a shift in sentiment as investors rotated into value opportunities, CSL shares were down by 5.9%. There was an even larger fall of 7.9% in the value of CSL holdings in the Selfwealth community as sell orders dominated trading activity.Taking pole position was none other than Commonwealth Bank (ASX: CBA), which until now has been an ever-present name in second place. But the nation largest bank had a positive month, up 4.2%, with its corporate buyback underpinning a rally in the company shares. The buyback, since wrapped up at a 14% discount, struck a chord with investors given the tax benefits involved. However, it remains to be seen if CBA presence atop the charts was an aberration, as holdings are expected to drop on the back of members parting with the shares they sold via the buyback.With iron ore prices at one stage sinking to as low as US$90 per tonne, iron ore miners took a backwards step. BHP (ASX: BHP) fell from 6th place to 8th position, while Fortescue Metals Group (ASX: FMG) also eased a couple spots to feature as the 11th most-held stock among Selfwealth members. Meanwhile, Rio Tinto (ASX: RIO) was nudged out of the top 20 altogether.Whereas most of the popular stocks held within the Selfwealth community had a rough month, travel shares maintained the positive momentum they enjoyed from August. Qantas (ASX: QAN) ended the month as the 16th most-held stock, while Flight Centre (ASX: FLT) held its position in 14th despite significant profit taking among Selfwealth members. Central to their performance was Australia accelerating vaccination program and the prospect of international travel reopening.After an absence in August, Woodside Petroleum (ASX: WPL) reappeared in the top 20, spurred on by soaring energy prices. There was also a return from Selfwealth (ASX: SWF), and a debut from pharmaceutical company Incannex Healthcare (ASX: IHL), although these two results were largely driven by a small number of holders with significant holdings in their Selfwealth trading accounts.ASX StockCompany1CBACommonwealth Bank2CSLCSL Limited3WBCWestpac4NABNational Australia Bank5AFIAustralian Foundation Inv6MQGMacquarie Group7ANZAustralia and New Zealand Banking Group8BHPBHP9TLSTelstra10Z1PZip Co11FMGFortescue Metals Group12APTAfterpay13WESWesfarmers14FLTFlight Centre15WPLWoodside Petroleum16QANQantas17SWFSelfwealth18IHLIncannex Healthcare19NEUNeuren Pharmaceuticals20MLTMiltonAs has become a common sight in recent months, the top 10 ETFs featured the same names, although the BetaShares Asia Technology Tigers ETF (ASX: ASIA) slipped into 10th place. That came on the back of a sell-down in Asian equities, largely sparked by concerns that a default for Evergrande could trigger a wave of financial chaos among other companies in China.Just outside the top 10, however, the BetaShares Global Sustainability Leaders ETF (ASX: ETHI) has gained particular popularity among Selfwealth members, with the fund attracting a higher value of holdings than some direct shares mentioned above like Woodside Petroleum and Qantas.ASX ETFsCompany1VASVanguard Australian Shares Index ETF2VDHGVanguard Diversified High Growth Index ETF3VGSVanguard MSCI Index International Shares ETF4VTSVanguard U.S. Total Market Shares Index ETF5IVVIshares S&P 500 ETF6A200BetaShares Australia 200 ETF7NDQBetashares Nasdaq 100 ETF8VEUVanguard All-World ex-U.S. Shares Index ETF9VHYVanguard Australian Shares High Yield ETF10ASIABetaShares Asia Technology Tigers ETF

ASX share trading activity

By far the most prevalent trend last month was the heightened level of trading in ETFs. Volatile market conditions almost certainly contributed to the trend, with Selfwealth members likely favouring ETFs as a method with which to retain exposure to the market through diversified funds.

In total, 8 ETFs were among the 20 most-traded stocks throughout September, a record level of interest in ASX funds as volumes soared. The Betashares Nasdaq 100 ETF (ASX: NDQ), iShares S&P 500 ETF (ASX: IVV) and BetaShares Australia 200 ETF (ASX: A200) were among the major movers, returning into the leaders list after varying absences. As touched on earlier, Selfwealth members were eager to take profits and sell into the rally in Flight Centre shares, even as the stock continued to climb more than 20% across the month. Just one-third of all FLT shares (by value) traded through the Selfwealth platform were buy orders, suggesting much of the buying strength supporting the stock rally was coming externally. Nonetheless, the move also prompted a number of momentum traders to jump in for short-term trades.

Elsewhere, a new multi-year low from AGL Energy (ASX: AGL) prompted interest from buyers betting on a turnaround in the energy company. The wholesale energy market has proven a drag for AGL over the last year and a half amid industry headwinds. Meanwhile, the company demerger plans have also fallen short of expectations among some. However, with 56% of all trades (by value) being buy orders, it appears some Selfwealth members believe the stock could be a value play.

For the second month in a row, the popularity of the battery metals theme was on full display, with five high-profile names from August reappearing on investors and traders screens throughout September.

Lithium names Vulcan Energy Resources (ASX: VUL) and Pilbara Minerals (ASX: PLS) remain two of the most-traded names across the Selfwealth community. The battery metals thematic has resonated with a number of Selfwealth members, and the added volatility affecting growth stocks last month meant that trade numbers were at a peak, totalling almost 4,000 between the duo.It was the same theme that also saw prominent interest in Lake Resources (ASX: LKE), recent debutant Kuniko (ASX: KNI), and Novonix (ASX: NVX), which were the 15th, 16th and 17th most-traded stock when measured by the number of orders filled. Combined, the trio were also at the centre of about 4,000 trades, suggesting interest in the minerals and technology to support EV development is of great intrigue to Selfwealth members.Top 20 stocks traded by valueCode SecurityBuy-Sell Ratio1FMGFortescue Metals Group57.6%2VASVanguard Australian Shares Index ETF70.4%3ANZANZ50.0%4BBOZBetashares Australian Equities Strong Bear Hedge Fund49.4%5WBCWestpac45.0%6Z1PZip Co49.2%7GEARBetaShares Geared Australian Equity (Hedge Fund)53.1%8BHPBHP59.4%9VDHGVanguard Diversified High Growth Index ETF88.1%10FLTFlight Centre33.5%11NDQBetashares Nasdaq 100 ETF70.6%12VGSVanguard MSCI Index International Shares ETF87.5%13CBACommonwealth Bank49.2%14TLSTelstra50.0%15VULVulcan Energy Resources58.4%16PLSPilbara Minerals59.3%17IVViShares S&P 500 ETF67.0%18A200BetaShares Australia 200 ETF78.5%19AGLAGL56.3%20CSLCSL40.8%

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