As far as bond buyers go, the Federal Reserve is pretty laid-back.

Even as the central bank amassed trillions of dollars of debt to prop up the economy following the financial crisis, it didn't hedge its holdings or worry about gains and losses that might keep ordinary investors up at night. This extreme buy-and-hold stance has had an incredible calming effect on the bond market. Volatility has plummeted to lows rarely seen in recent memory.

But all that is now poised to change. With interest rates on the rise, analysts say the Fed could start shrinking its unprecedented $1.75 trillion position in mortgage-backed securities by year-end. That's likely to leave more in the hands in private investors and result in increased hedging activity, a practice that has historically exacerbated swings in the Treasury market.