As the date for voting on the takeover gets closer, BSG's price will more closely track CDE's.
At present, it's like a lame duck. There's no point in buying it for its own sake, and most Australian investors don't know much about CDE, so the buying interest is limited.
If it gets close to the takeover date (say, a month) and the price differential remains, buyers will come in simply because of the arbitrage. However, BSG has now stopped trading on its own merits. From now on, it's at the whim of CDE's price movements. The only reason it might go up is if someone wants exposure to CDE.
Azteca
BSG Price at posting:
0.0¢ Sentiment: ST Sell Disclosure: Held