Oil and gas producers look particularly vulnerable to this year’s selling within Canada’s S&P/TSX Composite Index, as Covid-19 pushed oil to record lows earlier this year during strict lockdowns.

Vermilion Energy Inc. and Enerplus Corp. are among drillers that have fallen more than 60% this year. Twenty-one of the 23 stocks in the TSX energy index have declined at least 15%.

Toronto’s 222-member index has 41 companies that have fallen more than 20% this year, according to data compiled by Bloomberg. Air Canada, down more than 50%, has suffered from pandemic travel restrictions. Marijuana producer Aurora Cannabis Inc. has fallen 64% despite recent optimism that a Biden presidency will benefit the sector. The benchmark is up 1.24% this year.

Dec. 29 is the final day for tax-loss selling for investors seeking to post a capital loss in calendar 2020, according to National Bank ETF strategists led by Daniel Straus.

Meanwhile, Canaccord Genuity is recommending some opportunities during this period. Torc Oil & Gas Ltd., Allied Properties Real Estate Investment Trust and SNC-Lavalin Group Inc. are among potential tax-loss selling candidates that are expected to recover, analysts Doug Taylor and Javed Mirza said in a note.

Canaccord also highlighted some “switch trade” ideas where investors can swap out a position. The firm sees an opportunity to own Aritzia Inc. as its peer Gildan Activewear Inc. could see more selling pressure. Knight Therapeutics Inc. is also a tax-loss candidate, and investors may look to own HLS Therapeutics Inc. instead, the analysts said.