Mark Zuckerberg has dreamed of floating Facebook on the US stock market for more years than he would like to admit. Ivan Glasenberg, chief executive of commodities trading house Glencore, has wanted to buy Xstrata, the mining group, for even longer.

And here's a funny thing. Both the two 'bergs - Zuckerberg and Glasenberg - have decided to seek their hearts' desire at precisely the same time. Add the potential value of Facebook to the market capitalisation of Glencore and Xstrata, and you end up with a potential bet of $200bn that the equity market is set fair.