Talking point: The underwriters have a 15 per cent over-allotment option, so proceeds could rise to $460 million if it’s exercised. The IPO values the Brampton, Ont.-based company at $1.6 billion. Shares are expected to start trading on the Toronto Stock Exchange in the middle of next week under the symbol MDA. Investors were hesitant about the offering, in part, because of newly issued stocks recently falling in price, a source told The Globe and Mail. An investor consortium repatriated MDA from a Colorado-based company for $1 billion in December 2019. The Canadian entrepreneurs who bought it are still expected to almost triple their investment, even at the new lower valuation.