Tibco Software shares jump 20 percent in heavy volume

NEW YORK (Reuters) - Shares of Tibco Software were up 20.9 percent after the business software maker said private equity firm Vista Equity Partners would take it private for $4.3 billion in the largest technology buyout this year.

The stock was among the day's biggest percentage gainers on the Nasdaq and was trading in heavy volume of 49 million shares, compared with the stock's 10-day moving average volume of 5.6 million.

The stock's increase would be its biggest daily percentage gain since 2002. The shares are up 5 percent for the year so far, and jumped 6.6 percent last Wednesday. They are well above their intrinsic value of $9.54, according to Thomson Reuters StarMine data, suggesting the stock is overvalued.

The stock also has a relative valuation score of just 11 out of 100, the data showed.

Index snapshot at 11:49 EDT:

* S&P 500 was falling 5.83 points, or 0.29 percent.

* Nasdaq Comp was losing 6.78 points, or 0.15 percent.

* Dow industrials was dropping 56.79 points, or 0.33 percent.

* Russell 2000 was falling 1.4 points, or 0.13 percent.

* S&P MidCap was dropping 2.69 points, or 0.19 percent.

* S&P SmallCap was losing 0.93 points, or 0.14 percent.

(Editing by Nick Zieminski)