TLT

One options chain that presents an interesting outcome might be the June contract for long dated treasuries. Call options are all selling off, while put options are being bid:

http://quotes.ino.com/options/?s=CBOT_ZB.M13.E

Each futures contract on long dated treasury options represents a $100,000 treasury bond. By contrast, each gold futures contract represents 100 oz. of bullion. So bullion contracts are more valuable than treasury contracts, though the amount of money in treasuries is orders of magnitude larger than in gold.

Gold futures contracts are bid up to much larger face values than treasury bond futures contracts, because of the speculative nature of the contract. Treasury bonds futures contracts expire quarterly, while precious metals contracts expire monthly.

Very likely the gold sell-off is meant to affect June contract prices, though I can see price declines as a result of panic dishoarding in the effort to raise cash to settle failures to deliver on treasury bonds.

TLT is selling off:

http://scharts.co/QbPCQ1

http://quotes.ino.com/charting/?s=CBOT_ZB.M13.E

Given that GBN.V has been strongly inversely correlated with U.S. treasury bond prices over the long term, the share price aught to be subject to a buy-in on fresh lows in treasuries.

-F6