The NYSE-listed stock fell approximately 5.46% in the two days following the announcement, closing at $2.10 on Tuesday, from a 2015 high of $3.72 in late April.

So what does Zhang — who has vowed to finance the proposed privatisation through a mix of debt and equity capital — have in mind? 

Analysts say the stock has long been undervalued, plunging roughly 35% through the summer to $1.88 in late September — its lowest point since June 2013. Which is puzzling, given the strength of its business.