Bond Oddity: 10-Year Treasury Yield Rising, Even as Stocks Rally

A rally in stocks(today's gains were the biggest in nearly four weeks) has caused havoc in the bond market, with the yield on the 10-yearTreasury note doing something we don't see often—backing up considerably (yield rising, price falling.)

Is this a sign of a bubble?

"Absolutely not," Guy Lebas, director of fixed income strategy at Janney Montgomery Scott, told CNBC's "The Strategy Session" on Friday. (Check latest Treasury yields here.)

"A bubble requires at least one thing, which is that people are buying investment with the hopes of selling it at a later point at a higher price. People and institutions are buying bonds for their return, for their yield and for their level of safety,"Lebas said.

One major factor that is often overlooked, according to Lebas, is our aging population. Something that he thinks will be dominating the markets over the next decade.

These are many of the same concerns that affected Japanin the early '90s, which in a smaller way are impacting the US economy and markets right now—low yields for an extended period," he said.

"The average age to retirement of many of the S&P 500 companies' pensions is dipping below ten years right now." These pension funds control huge amounts of money and "are looking to shed some of their capital depreciation assets like stocks and move over to the bond market," Lebas concluded.