(Adds byline, details from results, share price in paragraphs 5-13)
Nov 3 (Reuters) - Bad weather weighed on results at Warren Buffett's Berkshire Hathaway Inc, as losses from insurance claims tied to Hurricanes Harvey, Irma and Maria and an earthquake in Mexico contributed to a 43 percent drop in third-quarter profit.
Berkshire on Friday said net income fell to $4.07 billion, or $2,473 per Class A share, from $7.2 billion, or $4,379 per share, a year earlier.
Operating profit, which excludes investment and derivative gains and losses and which Buffett says better reflects company performance, fell 29 percent to $3.44 billion, or $2,094 per Class A share, from $4.85 billion, or $2,951 per share.
Berkshire said it incurred $1.95 billion of after-tax underwriting losses attributable to the hurricanes and earthquake.
Analysts on average expected operating profit of $2,402.47 per share, according to Thomson Reuters I/B/E/S.
Berkshire, which the 87-year-old Buffett has run since 1965, has roughly 90 businesses in such sectors as chemicals, energy, food and retail and industrial products.
But its diversification helped cushion the overall profit decline, including profit gains of 2 percent at the BNSF railroad and 3 percent at Berkshire Hathaway Energy.
Book value per Class A share, measuring the Omaha, Nebraska-based conglomerate's assets minus liabilities, rose 2.5 percent from the end of June to $187,435, and is up 8.9 percent this year.
Berkshire lost $1.44 billion from insurance underwriting in the quarter, and $1.73 billion from January to September, putting it on pace for its first full-year underwriting loss since 2002.
It had even eked out a small underwriting profit in 2005, the year of Hurricanes Katrina, Wilma, Rita and Dennis.
But investment income from insurance operations cushioned the blow, rising 23 percent to $1.04 billion.
Investors have remained confident in Berkshire's prospects, and have boosted its share price 15 percent this year.
The Class A shares closed Friday down $2,963.99 at $280,470.01, while Class B shares fell $1.34 to $187.27. Both were about 2 percent below their Oct. 24 record highs. (Reporting by Jonathan Stempel in New York; Editing by Susan Thomas and Richard Chang)