Although December has typically been associated with a stock market Christmas Rally, the seasonal trend failed to eventuate last month as the ASX 200 fell 2.4%.

The worst-performing segments were the consumer staples sector, down 8.1%, followed by the telecommunications and IT sectors, which dropped 5.8% and 4.6% respectively. Shares from the materials sector were one of the only bright spots across the ASX, trading 1.5% higher.

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

Which shares and ETFs were the most held?

The top 20 shares held within the Selfwealth community throughout December remained the same as that of the month prior, however, there were some adjustments to the order in which they featured.

CSL Limited (ASX: CSL) once again topped the charts, followed by the Big Four banks. In light of the poor result from the market during December, it was no surprise that each of these stocks fell in proportion with the index. With three of the banks paying dividends mid-month, it appears some of these proceeds were reinvested back into shares as the total value held for each of the aforementioned stocks increased by a modest percentage.Neuren Pharmaceuticals (ASX: NEU) continued its ascent, climbing up one spot to become the 7th most-held stock by Selfwealth members. During the month, the company issued an end-of-year update and outlook for the year ahead, confirming that it met two of its key drug development milestones.Another key stock to make a charge up the list was Woodside Petroleum (ASX: WPL). Despite the company shares falling 0.4%, positive sentiment followed the stock on account of the sharp increase in the price of oil across the month. The commodity price surged by double-digit figures, reaching a three-month high.Cochlear (ASX: COH), Woolworths (ASX: WOW) and Afterpay (ASX: APT) were among the stocks which saw their ownership, as measured by the total value of stock held, diminish within the Selfwealth community. This is explained by the sharp fall in the market cap of each of these companies, which were lower by 4%, 9.1% and 7.3% respectively. In the case of Woolworths, investors appeared skittish about the prospect of a class action against the company relating to payment shortfalls for staff.StockCompany1CSLCSL Limited2CBACommonwealth Bank3WBCWestpac4NABNational Australia Bank5ANZAustralia and New Zealand Banking Group6AFIAustralian Foundation Inv7NEUNeuren Pharmaceuticals8MQGMacquarie Group9TLSTelstra10BHPBHP11ARGArgo Investments12MLTMilton Corp13WPLWoodside Petroleum14COHCochlear15WOWWoolworths16WESWesfarmers17RIORio Tinto18APTAfterpay19RHCRamsay Health Care20A2MThe a2 Milk CompanyThere was only one change among the top ten ETFs held by members of the Selfwealth community. The Vanguard Australian Property Securities Index ETF (ASX: VAP) slid into 10th position, edging out the Vanguard Australian Shares High Yield ETF (ASX: VHY). The new addition underperformed the market in terms of capital appreciation, falling 4.1%, however, many real estate shares traded ex-dividend during December and this seasonality may explain increased ownership of the VAP ETF.ETFCompany1VASV300AEQ/ETF2VGSVINTL/ETF3VDHGVDHIGHGROW/ETF4VTSVUSTOTAL/ETF5IVVISCS&P500/ETF6A200BETAAUS200/ETF7VEUVWORLDXUS/ETF8STWSPDR S&P/ASX 200 Fund9NDQBETANASDAQ/ETF10VAPV300APROP/ETF

Which shares and ETFs were the most traded?

While the market performed poorly in December, the weight of buying volume to selling volume increased from November result despite trending lower the month prior. A bias towards buying activity aligns with one of the key reasons that seek to explain the Santa Rally', even if it ultimately didn't transpire in this instance. Buying volume across all stocks was 1.5x that of selling volume.

PurchasesCodeSecurity1VASV300AEQ/ETF2BBOZBETA SBEAR/FD3FMGFortescue Metals Group4CSLCSL5VDHGVDHIGHGROW/ETF6IVVISCS&P500/ETF7VGSVINTL/ETF8WBCWestpac9APTAfterpay10STWSPDR S&P/ASX 200 Fund

SalesCodeSecurity1BBOZBETA SBEAR/FD2FMGFortescue Metals Group3WBCWestpac4APTAfterpay5CSLCSL6BHPBHP7A2MA2 Milk8ANZAustralia and New Zealand Banking Group9STWSPDR S&P/ASX 200 Fund10APXAppen

For the second month in a row, there was a marked increase in the value of bearish' bets placed against the Australian stock market, however, this appears to be driven by a small number of investors. Buying volume in the Australian Equities Strong Bear Fund (ASX: BBOZ) almost doubled, just as it did during November, making it the second-most bought stock by value last month. Although the same stock remains the most-sold instrument within the community as well, the ledger has narrowed substantially to less than 10% differential between buy and sell volume.One observation among the most-bought stocks points towards a clear trend, with ETFs gaining in popularity across the month. Investors took the opportunity to stock up on the likes of the Vanguard Diversified High Growth Index ETF (ASX: VDHG), iShares S&P 500 ETF (ASX: IVV), Vanguard MSCI Index International Shares ETF (ASX: VGS) and the SPDR S&P/ASX 200 Fund (ASX: STW).The above funds, none of which featured in the leading stocks bought during November, gained traction over blue-chip favourites such as Commonwealth Bank (ASX: CBA), ANZ (ASX: ANZ), Telstra (ASX: TLS) and BHP (ASX: BHP). Each of these blue-chip names fell out of the top 10 stocks bought by Selfwealth members, suggesting investors were favouring a more balanced and diversified portfolio as the index lost momentum.All but two of the stocks that were under selling pressure in November featured again in the top 10 list for December. CSL (ASX: CSL), however, joined the list in place of Telstra (ASX: TLS), which might be attributed to profit taking.

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