UPDATE 1-BlackRock's Fink says letter to CEOs triggered angry phone calls

(Adds further comment from BlackRock CEO)

BOSTON, May 28 (Reuters) - BlackRock Inc Chief Executive Larry Fink, who runs the world’s largest asset manager, said Wednesday he had fielded angry phone calls after he sent a letter in March to S&P 500 executives warning them about the perils of short-term thinking.

“I’ve had some really angry phone calls,” Fink said at a New York investment conference hosted by Sanford Bernstein.

He did not name any of the callers.

In the March 21 letter, Fink warned against relying too much on dividends and buybacks to produce quick returns at the expense of long-term investment.

He knew the letter would be “kind of edgy,” said Fink, who had never encountered such an outcry during his professional career.

Fink said he realized a few years ago that managing index funds carried more responsibility than overseeing actively managed assets. BlackRock, which oversees more than $4 trillion in client assets, is the world’s largest exchange-traded fund manager with nearly $1 trillion in ETF assets.

“As an index fund manager, you have to really own some crummy companies that you have in your index,” Fink said. “Your horizon has to be long term.”

In contrast, actively managed funds can sell a stock if they don’t care for a company’s management team, Fink said.

He described his letter as a wake-up call to investors to focus on long-term outcomes.

“In the wake of the financial crisis, many companies have shied away from investing in the future growth of their companies,” Fink wrote in the March letter.

“Too many companies have cut capital expenditure and even increased debt to boost dividends and increase share buybacks. ... It can jeopardize a company’s ability to generate sustainable long-term returns.” (Editing by Meredith Mazzilli and Bernadette Baum)