In afternoon trade, the S&P/ASX 200 Index (ASX: XJO) is on course to record another gain. At the time of writing, the benchmark index is up 0.5% to 7,825.6 points.

Four ASX shares that have failed to follow the market higher today are listed below. Here's why they are falling:

The Brickworks share price is down over 2% to $27.02. This has been driven largely by the building products company's shares going ex-dividend this morning for its upcoming interim dividend. Last month, the company released its half-year results and declared a fully franked interim dividend of 24 cents per share. This was up 4% on the prior corresponding period, representing its 10th annual increase in a row. Brickworks shareholders can look forward to receiving this dividend at the very start of next month on 1 May.

The Flight Centre share price is down 2% to $21.20. This appears to have been caused by a bearish broker note out of Goldman Sachs this morning. According to the note, its analysts have downgraded the travel agent's shares to a sell rating with a trimmed price target of $18.30. This implies potential downside of approximately 14% for investors from current levels. Goldman Sachs warned that "moderating corporate travel and intensifying SME competition could lead to margin disappointment."

The Heartland share price is down 5% to $1.06. This morning, this New Zealand based financial services company successfully completed the institutional component of a capital raising. Its placement and institutional entitlement offer raised gross proceeds of approximately NZ$131 million thanks to strong support from existing institutional shareholders and new institutional investors. It notes that eligible institutional shareholders elected to take up 98% of their entitlements. Heartland will now push ahead with its retail entitlement offer.

The Spartan Resources share price is down over 10% to 60 cents. This follows the release of drilling results from the gold explorer's 100%-owned Dalgaranga Gold Project in the Murchison region of Western Australia. The assays include significant intercepts from exploration and resource extension drilling at the high-grade Never Never Gold Deposit, West Winds Gold Prospect, and the Sly Fox Gold Deposit. However, it seems that some investors were pricing in even stronger grades from the Never Never Gold Deposit. Nevertheless, Spartan's Chief Executive Officer, Simon Lawson, was "absolutely delighted to see a plus-20-metre down-hole intercept of typical Never Never-style mineralisation with visible gold logged in two areas."