In afternoon trade, the S&P/ASX 200 Index (ASX: XJO) is on course to record a strong gain. At the time of writing, the benchmark index is up a sizeable 1.9% to 8,872.6 points.
Four ASX shares that have failed to follow the market higher today are listed below. Here's why they are falling:

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Bougainville Copper Ltd (ASX: BOC)
The Bougainville Copper share price is down 3.5% to 79 cents. Investors have been selling this copper stock after it announced the termination of a strategic partnering process with the president of the Autonomous Bougainville Government. This is in relation to the selection of an international mining partner for the redevelopment of the Panguna Mine.
Brainchip Holdings Ltd (ASX: BRN)
The Brainchip share price is down a further 3.5% to 13.5 cents. This semiconductor company's shares have come under significant pressure since the release of another disappointing quarterly update. Brainchip reported cash receipts of just US$0.4 million for the three months ended 31 December, despite entering the commercialisation stage a few years ago. Investors appear to be doubting whether Brainchip realistically has any chance of ever competing with chip developers that spend billions on research and development each year.
Challenger Ltd (ASX: CGF)
The Challenger share price is down 3.5% to $8.60. This follows news that the annuities company is in advanced talks to jointly acquire Pepper Money Ltd (ASX: PPM) with Pepper Group ANZ HoldCo. Challenger believes the potential acquisition would provide long-term access to fixed income assets and support its strategic growth plans. If completed, Challenger would hold no more than 25% of total Pepper Money shares. It seems that the market isn't overly keen on the deal.
HMC Capital Ltd (ASX: HMC)
The HMC Capital share price is down almost 5% to $3.73. This morning, Morgan Stanley retained its equal-weight rating and $3.85 price target on the investment company's shares. Its analysts think that HMC Capital's shares are fair valued at current levels. Though, it is worth noting that other brokers see more value in the company's shares. For example, last month Morgans put a buy rating and $6.60 price target on its shares. Based on its current share price, this implies potential upside of approximately 75% for investors over the next 12 months. Time will tell which broker has made the right call on this one.