SAN FRANCISCO – Two large publishers raised hopes Thursday that a harrowing financial slump is nearly over for the newspaper industry. That wasn’t enough to lift their shares, however.

First-quarter ad revenue at both The New York Times Co. and McClatchy Co. fell at the lowest rate in 2½ years — 6.1 percent and 11 percent, respectively — as an improving economy spurred companies to spend more money on marketing.

The trend is encouraging because newspapers rely on advertising for most of their income. To cope with the downturn, newspapers have laid off workers and cut other expenses. Even that hasn’t been enough to prevent more than a dozen newspaper companies from seeking bankruptcy protection during the past 16 months.

Despite the first-quarter progress, executives from the Times Co. and McClatchy declined to forecast when their companies will start growing again.

Investors evidently weren’t happy with that. McClatchy shares tumbled 71 cents, or 10.4 percent, to $6.12, while Times Co. shares fell 45 cents, or 3.5 percent, to $12.29. Both stocks had been rallying in the past month on the expectation of smaller declines in ad revenue.

One reason for the lessening advertising declines: more favorable comparisons. For instance, the Times Co.’s ad revenue plunged 27 percent in last year’s first quarter, dramatically lowering the bar that it had to measure up to this year.

“It’s really hard to categorize these results as great news because the first quarter of 2009 was a near-depression,” said newspaper analyst Ken Doctor of Outsell Inc. “Given that, you would want to be ahead of these comparisons, not behind them.”

The Times Co. earned $12.8 million, or 8 cents per share, in the first quarter. That compared with a loss of $74.5 million, or 52 cents per share, a year earlier.

McClatchy earned $2.2 million, or 3 cents per share, in the first quarter. It lost $37.5 million, or 45 cents per share, in the same period a year earlier.