In afternoon trade the S&P/ASX 200 (Index: ^AXJO) (ASX: XJO) is on course for an impressive start to the week. At the time of writing the benchmark index is up almost 1.4% to 5,696.9 points.

Four shares that have failed to follow the market higher today are listed below. Here’s why they have started the week in the red:

The Healius Ltd (ASX: HLS) share price has dropped 4% to $2.64 after the healthcare company’s board rejected a $3.25 cash per share takeover proposal from Jangho Hong Kong Limited. The Healius board unanimously believes that the proposal is opportunistic and fundamentally undervalues the company. It believes strategic initiatives that are underway will create greater value for shareholders.

The Macquarie Telecom Group Ltd (ASX: MAQ) share price has tumbled 3% to $20.22 despite there being no news out of the telecom and data services company. However, Macquarie Telecom’s shares are not the most liquid on the market, so swings of this nature can happen from time to time, not least on low volume days like today.

The St Barbara Ltd (ASX: SBM) share price has fallen over 4% to $4.78. St Barbara and the rest of Australia’s gold miners have dropped deep into the red today after investors gained an appetite for risk again and drove the spot gold price 1% lower over the last 24 hours. The S&P/ASX All Ords Gold index is down 2.2% at the time of writing. Northern Star Resources Ltd (ASX: NST) and Evolution Mining Ltd (ASX: EVN) are also acting as drags on the gold miners index.

The Tamawood Limited (ASX: TWD) share price is down 4% to $3.65 after the home building company announced a further downgrade to its profit guidance. Due to a “Perfect Storm” of negative factors, profit is expected to be down 26.9% in the first half of FY 2019. However, management believes the company is well placed to ride out the storm.