Pershing Square disclosed on Monday a 2.9 million-share stake in the laboratory instrument and software company in an SEC filing.
The filing from the September quarter was amended after having been filed in November.
Pershing Square said the investment had been omitted through a request for confidential treatment that was withdrawn on Dec. 9.
The Agilent stake was is valued at $246 million based on Monday's closing price.
|A||AGILENT TECHNOLOGIES, INC.||133.81||+1.30||+0.98%|
Agilent's stock gained nearly 4 percent to $84.68 in after-hours trading.
Agilent was a part of Hewlett-Packard until being spun off in 1999.