NEW YORK (CNN/Money) - In bond land, a big event begins today: the quarterly refunding. This happens four times a year when the Treasury department sells a bunch of new notes and bonds to take the place of the ones that are maturing.

Today $22 billion of 3-year notes are up for sale, followed by $15 billion in 5-year notes on Wednesday and $14 billion in $10 year notes on Thursday. In short, muchos bonds.

For the bond dealers who buy these bonds and then re-sell them to the investing public, it's a tricky week of trying to gauge demand for these securities at their current yield levels. But in the broader financial world the quarterly refunding is watched to see if big foreign investors are still hungry for U.S. bonds. Because if they start losing their appetite, then it will mean lower bond prices and higher bond yields -- all other things being equal -- and that could mean higher mortgage rates, more competition for stocks, and all that goes along with that.

Consider this: According to the economists at Deutschebank, the most recently available government statistics show that over 50 percent of foreign-held US Treasury securities belonged to Japan, China, Hong Kong, and South Korea.

"In the environment of a stubborn US trade deficit which seems to be defying the corrective forces of a weaker currency, the pressure mounts on these Asian economies to continue to buy US Treasury securities to prevent further depreciation of the dollar," they write in a note out today. "Today's auction results will provide an indication of whether or not that trend continues."

That's why the quarterly refunding is a big deal not just in bond land but for the rest of us, too.

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-- Kathleen Hays is economics correspondent for CNN and contributes to Lou Dobbs Tonight. You can read more of her columns here.