COLUMN-Sudden jump in zinc stocks threatens bull party -Andy Home

(Repeats without change. The opinions expressed here are those of the author, a columnist for Reuters)

* LME zinc stocks and arrivals: http://tmsnrt.rs/2FfxVT2

* LME zinc price and spreads: http://tmsnrt.rs/2Fiu57h

By Andy Home

LONDON, March 5 (Reuters) - A bucket of cold water has just been poured on zinc's bull fires.

The London zinc price has been on a two-year romp, hitting a 10-year high of $3,595.50 a tonne last month.

The bull run has been fuelled by a narrative of tightness, first at the raw materials stage of the supply chain and more recently in the refined metal segment of the market.

That narrative, however, has just been upended by the delivery of 78,950 tonnes of metal onto warrant at the London Metal Exchange (LME).

The "arrivals" showed up in today's LME stocks report and break a long-running downtrend in LME stocks.

Headline inventory has bounced back to the levels of early December.

Someone, it seems, is calling time on the zinc party.

Graphic on LME zinc stocks and "arrivals":

http://tmsnrt.rs/2FfxVT2

Graphic on LME zinc price and spreads:

http://tmsnrt.rs/2Fiu57h

SURPRISE!

Today's was the largest single-day "arrivals" event in LME zinc stocks since July 2013.

It's worth remembering that when this scale of tonnage shows up in the LME's daily stocks reports, the metal hasn't all just miraculously arrived and been warehoused overnight.

It has probably been accumulating for a while, biding its time until the owner hits a keyboard button to deliver it onto LME warrant, at which stage it "arrives" in the LME warehouse network.

The process still requires a fair amount of logistical coordination and the presumed intention was to spring a bear surprise on a bull market that has spent the past year watching LME inventory tick lower.

To judge by today's sell-off -- LME outright zinc sliding from an early high of $3,386 a tonne to $3,280 -- the surprise worked.

There were, however, some clues that something like this was brewing.

The downtrend in LME stocks was starting to look just a bit too neat and managed. Since the middle of November, the traffic has been exclusively one-way, barring a modest 200-tonne inflow on Feb. 26.

The zinc market has a history of this sort of false stocks signal and the apparent relentless draw on LME inventory has been accompanied by growing market chatter as to what might be lurking in New Orleans.

This U.S. port has long been a statistical black hole for physical zinc, with extended periods of LME draws interspersed with sporadic heavy inflow as material oscillates between on-market and off-market storage.