When is a safe-haven asset not a safe-haven play?

Leslie Shaffer | Writer for
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Safe-haven assets such as U.S. Treasurys and German government bonds may be rising amid increased geopolitical risks, but some analysts believe the gains aren't due to a flight-to-safety.

"It is not a rush to quality, but adjustment to very different sorts of economic expectations," Reorient research said in a note Monday.

Sovereign bond safe-havens have rallied, although some have attributed the move to climbing geopolitical risks, including the Russia-Ukraine conflict and fighting in Gaza, Syria and Iraq.

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The 10-year U.S. Treasury yield was around 2.43 percent in early Asian trade Monday, down from around 2.63 percent in early July, while Germany's 10-year bond yield was around 1.054 percent late last week, down from around 1.265 percent in early July. The U.K. 10-year gilts were around 2.46 percent late Friday, compared with around 2.76 percent in early July. Bond yields move inversely to prices.

But the reasons for the yields' decline are different for each region, Reorient said.

US Treasurys down for the week

In the U.S., it's rising inflation expectations, it said.

"It may seem counter-intuitive that bond yields might fall in response to rising inflation risk, but that can happen when the U.S. government creates a multi-hundred-billion-dollar market in inflation-protected securities," Reorient said, referring to the TIPS, or Treasury Inflation-Protected Securities, which rise in value along with inflation.

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The 10-year TIPS yield is trading around 0.15 percent, down from around 0.45 percent in early June, according to data from Reorient. This reflects the market's rising inflation expectations on a 10-year horizon, which has boosted the cost of insuring against those expectations, via TIPS, Reorient said.

But in Germany, the opposite is occurring, with inflation expectations declining, pushing up the yield on the country's 10-year inflation-linked paper, Reorient said.

"That tells us that the German bond market is trading on fears of deflation—the continued weakening of Europe's financial system starting with the still-depressed periphery," it said.

Reorient isn't alone in believing safe-haven plays aren't rising on a safe-haven play.

Read More Is the chase for yield running out of breath?

"While global markets have been buffeted by escalating geopolitical risks, we doubt that rising safe-haven demand has been the main driver of the fall in Gilt yields," Samuel Tombs, a U.K. economist at Capital Economics, said in a note Monday. He noted that the spread between Gilt yields and overnight index swap (OIS) rates would be expected to narrow in a safe-haven play, but instead the two rates are moving together.

Why rates could stay low for a while

"Instead, markets seem to be rightly reassessing the link between activity and inflation," Tombs said. "With strong growth in the U.K. still making only fairly minimal inroads into the amount of spare capacity in the economy, price pressures are unlikely to build soon."

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Tombs expects controlled inflation will keep Gilt yields from climbing much once official interest rates begin to rise, forecasting the 10-year yield to rise to around 2.75 percent by December and 3.25 percent by the end of 2015.

Some point to another reason for the continued interest in safe-haven assets: supply and demand.

Read More Will rising Treasury yields really whack EM?

"There is not enough of the right kind of high-quality liquid debt from the safest of issuers, like the U.S. government, actually available," Steven Major, global head of fixed-income research at HSBC, said in a note last week.

He noted that the declining budget deficit means supply is about half its level 18 months ago. HSBC is "mildly bullish" on U.S. Treasurys. It expects the U.S. 10-year yield will fall to 2.10 percent on a six-month horizon, before rising to around 2.50 percent on a 12-month view. HSBC also forecasts German 10-year bond yields will fall to 0.95 percent on a six-month view before rising to 1.30 percent of a 12-month horizon.

—By CNBC.Com's Leslie Shaffer; Follow her on Twitter @LeslieShaffer1