By Ellie Ismailidou, MarketWatch

Treasury yields closed below 2% on Friday, after a week of much fluctuation but light trading volumes, as liquidity dried up and new supply hit the market.

Throughout the week, the market seemed to shrug off economic data, rather driven by two main themes: the hangover from the post-Fed buying rally that started last week and the shrinking liquidity as auctions of two-, five- and seven-year Treasury notes kept pushing new supply into the market.

The yield on the benchmark 10-year Treasury note dropped 6.1 basis points to 1.946% on Friday, after crossing over the 2% threshold on Thursday and posting the largest two-day gain since Feb. 17, according to Tradeweb. Overall it gained 1.4 basis points throughout the week. Bond prices move inversely to yields.

The two-year note yield fell 3.9 basis points to 0.583%, and the 30-year bond yield declined seven basis points to 2.529%.

The main driving force in the market on Friday was as a report that showed an updated reading on U.S. economic growth held steady at 2.2% in the fourth quarter of 2014.

Investors had expected the growth rate (http://www.marketwatch.com/story/4th-quarter-gdp-unchanged-at-22-exports-consumers-stronger-2015-03-27)to be revised higher, so the unchanged reading gave a bullish undertone to the market.

"This is a small rally that shouldn't come as a surprise, after two down days in a row," said Chris Keith, portfolio manager at Newton, Mass.-based Adviser Investments.

Wednesday's and Thursday's increase in yields reversed a downward trend that started last week with a brisk rally after the Federal Reserve indicated that it likely would raise rates at a slower pace than expected.

Some investors are taking advantage of the higher yields hoping to make gains; but the trend will likely not be sustained and yields will resume their upward course, Keith said.

The lower trading volumes throughout the week have to do with the fact that balance sheets around Wall Street have been very carefully managed over the last couple of years and the restrictions get tighter and tighter as more regulation comes into play, explained Thomas Simons, an economist at Jefferies & Co.

This intensifies the effect that cash coming into and out of the Treasury market has on yields, he added.

Throughout the week the market took out a $90 billion package of auctions with mixed results, as the two-year auction was well received for the 10th straight month whereas both the five (http://www.marketwatch.com/story/auction-of-5-year-treasurys-sees-lowest-demand-since-2009-2015-03-25)- and seven-year (http://www.marketwatch.com/story/seven-year-treasury-auction-sees-weak-demand-2015-03-26) auctions saw weak demand, Simons said.

The weak demand on the five- and seven-year auctions put enough pressure on prices in the secondary market to drive yields up on Wednesday and Thursday.

At its core this is a liquidity issue, Keith argued.

The poor showing for the auctions also shows that investors don't see the same value that they did previously in Treasury bonds at these levels and at this time, Keith said.

"We all knew this rally would end and now that we are getting closer to the end date investors are weary about going in," Keith said.

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