NEW YORK Feb 14 Warren Buffett's Berkshire
Hathaway Inc was an aggressive buyer of stocks in last
year's fourth quarter, disclosing significant increases in its
stakes in Apple Inc and in the four biggest U.S.
In a regulatory filing, Berkshire said it nearly quadrupled
its stake in Apple to about 57.4 million shares, worth roughly
$6.64 billion as of Dec. 31, from 15.2 million shares three
months earlier. It also disclosed year-end stakes worth more
than $2 billion each in American Airlines Group Inc,
Delta Air Lines Inc, Southwest Airlines Co and
United Continental Holdings Inc.
(Reporting by Jonathan Stempel in New York; Editing by Leslie