The S&P/ASX 200 (Index: ^AXJO) (ASX: XJO) has had a reasonably positive start to the week. In afternoon trade the benchmark index is up 0.1% to 5,772 points.
Four shares which haven't had a great start to the week are listed below. Here's why they are starting the week in the red:
The Aconex Ltd (ASX: ACX) share price has tumbled 3% to $3.88 despite there being no news out of the software-as-a-service company. This latest decline means that its shares have lost around 23% of their value this year. But with its performance improving, now could arguably be a good time to consider an investment.
The Galaxy Resources Limited (ASX: GXY) share price has fallen 4% to $1.85 following the release of its quarterly update. Investors appear to be disappointed with the slight rise in cash costs per tonne during the quarter. However, it is worth noting that whilst costs were higher during the quarter, costs in the month of June were considerably lower and a big improvement on the previous quarter.
The Medibank Private Ltd (ASX: MPL) share price is down 3.5% to $2.80. As well as its CEO Craig Drummond being decidedly negative about the health insurance industry, Medibank's shares came under pressure today following a broker downgrade. According to a note out of Goldman Sachs, its analysts have downgraded Medibank to a sell rating with a $2.46 price target. Goldman believes that current trends make the private health insurer's margins unsustainable.
The Northern Star Resources Ltd (ASX: NST) share price has fallen 2.5% to $4.40. Unfortunately this is the second trading session of declines in a row for the gold miner. The catalyst for this appears to have been a research note out of UBS on Friday which rated Northern Star as a sell with a $4.49 price target. Although the miner has now fallen below this price target, I wouldn't be in a rush to invest.