There's no doubt steel would have helped most investors' portfolios over the past year. More accurately, shares of a steel producer like U.K.-based Rio Tinto plc (RTP).

RTP shot up 23%, to $440.20 per share, Thursday on talk of a takeover bid from Australian rival BHP Billiton Ltd (BHP). On Friday, jubilant traders tacked on another 9% to RTP's price, pushing the stock to $476.35. RTP shares gave ground on Monday after BHP set a price on the deal, before recovering to $447.25 yesterday.

Just a year ago, RTP was languishing in the low $200s.

Gold bugs take note: You're losing money. Relative to steel, that is. Bullion's risen in value nearly 30% in the past 12 months while mining stocks, as measured by the Amex Gold Miners Index, are up 24%. RTP, as of yesterday, is up 11% over the same period. RTP, too, is a component of the Amex Steel Index, which itself has climbed 83%.

Now, that's the good news. The bad news is that RTP is brushing off the BHP deal. Three BHP shares are being offered for each RTP share which, according to BHP, amounts to a 15% premium over RTP's November 7 share price.

True enough. On November 7, RTP's American Depository Receipts ended the day at $357.50. Tack on the premium and you get $411 per share. RTP shares, however, were talked up to $484 at one point, so now the deal looks lowball. Whether RTP's board will shop around for a better deal remains to be seen.

BHP, for its part, is still trying to cajole RTP's board to hit the bid. CEO Marius Klopper says a combined operation would be better able to satisfy China's hunger for steel. Think of that as code-speak for "pricing power."