The S&P/ASX 200 Index (ASX: XJO) is running out of steam and fighting hard to stay in positive territory. In afternoon trade, the benchmark index is up slightly to 8,230.9 points.

Four ASX shares that are weighing on the market today are listed below. Here's why they are falling:

CAR Group Limited (ASX: CAR)

The CAR Group share price is down 1.5% to $37.98. This appears to have been driven by a broker note out of Ord Minnett this morning. According to the note, the broker has downgraded the auto listings company's shares to a hold rating with a $39.00 price target. The broker made the move on valuation grounds after a strong gain on Tuesday drove its shares to a level that is deemed to be fairly valued now.

Myer Holdings Ltd (ASX: MYR)

The Myer share price has continued its slide and is down a further 3% to 81.7 cents. This department store operator's shares are now down almost 30% since this time last week. Investors have been selling Myer's shares following the release of a disappointing trading update. For the 22 weeks ended 28 December, group comparable sales were in line with the prior corresponding period, but total sales were down 0.8% to approximately $1,592 million. And weaker margins led to Myer's EBIT falling approximately 25% to $48 million.

Neuren Pharmaceuticals Ltd (ASX: NEU)

The Neuren Pharmaceuticals share price is down 9% to $10.94. This morning, this pharmaceuticals company announced that its partner Acadia Pharmaceuticals (NASDAQ: ACAD) has submitted a Marketing Authorization Application (MAA) to the European Medicines Agency (EMA). This is for trofinetide for the treatment of Rett syndrome in adults and paediatric patients two years of age and older. Acadia anticipates potential approval in the first quarter of 2026. If granted marketing authorisation, trofinetide will be the first and only approved therapy for Rett syndrome in the European Union. The approval timeframe may be longer than some were expecting.

Yancoal Australia Ltd (ASX: YAL)

The Yancoal Australia share price is down 1% to $5.89. This follows news that the coal miner's CEO is stepping down. Yancoal advised that David James Moult will resign after seven years with the company and five years as CEO. Mr Moult decided to retire from full-time employment to devote more time to his other business engagements. His employment will end on 14 July 2025, but active duties have ceased immediately.