UPDATE 1-Equity Residential first-quarter FFO falls slightly

(Adds outlook, net operating income, CEO quote, share activity)

NEW YORK, April 30 (Reuters) - Equity Residential EQR.N, one of the largest U.S. apartment owners, said on Wednesday that quarterly funds from operations fell slightly due in part to lower gains on sales of condominiums.

The real estate investment trust reported first-quarter FFO available to common shareholders of $170.7 million, or 59 cents a share, compared with $173 million, or 55 cents per share, in the year-ago quarter, when the there were fewer shares outstanding.

The results met the analysts' average call for FFO, according to Reuters Estimates, and was at the high end of the company's forecast of 56 cents to 60 cents per share.

FFO, a REIT performance measure, removes the profit- reducing effect of depreciation -- a noncash accounting item -- on earnings.

For properties the company has owned for at least a year, net operating income rose 4.7 percent, driven primarily by rent increases.

The company, founded by real estate magnate Sam Zell, ended the quarter with its apartments 95 percent occupied.

"Despite a slowing economy and disappointing job numbers, apartment fundamentals remain fairly healthy across most of our markets," David Neithercut, Equity Residential's chief executive, said in a statement.

For the second quarter, the company sees FFO in the range of 61 cents to 65 cents per share.