(Rewrites paragraph 1 to focus on earnings beat; adds investment income in paragraph 3, short seller background in paragraph 4)

Feb 15 (Reuters) -

Canadian insurer Fairfax Financial Holdings on Thursday beat estimates for fourth-quarter profit, helped by higher gains from investments.

Firming bets that central banks will cut rates this year are fuelling a stock market rally, which has driven strong gains on investments for companies with substantial exposure to equities.

Fairfax's equity exposure drove net gains from investments to $2.13 billion in the fourth quarter, up from $1.09 billion last year.

The earnings beat comes just a week after Muddy Waters said it had taken a short position in Fairfax, citing manipulation in its asset values.

Fairfax has rejected the short seller's report, calling it "false and misleading."

Net insurance revenue was up at $5.68 billion from $5.31 billion in the year-ago period.

The Toronto-based insurance company posted a consolidated combined ratio of 89.9% in its property and casualty insurance and reinsurance segment, compared with 90.9% a year earlier.

A ratio below 100 means that the insurer earned more in premiums than it paid out in claims for the period.

Net earnings were $1.67 billion, or $52.87 per share, for the three months ended Dec. 31. Analysts on average expected a profit of $52.15 per share, as per LSEG estimates.

(Reporting by Pritam Biswas in Bengaluru; Editing by Anil D'Silva)