By Ross Kerber

BOSTON, Nov 28 (Reuters) - Stock-picking fund managers are testing their investors' patience with some of the worst investment returns in decades.

With bad bets on financial shares, missed opportunities in technology stocks and too much cash on the sidelines, roughly 85 percent of active large-cap stock funds have lagged their benchmark indexes through Nov. 25 this year, according to an analysis by Lipper, a Thomson Reuters research unit. It is likely their worst comparative showing in 30 years, Lipper said.

Some long-term advocates of active management may be turned off by the results, especially considering the funds' higher fees. Through Oct. 31, index stock funds and exchange traded funds have pulled in $206.2 billion in net deposits.

Actively managed funds, a much larger universe, took in a much smaller $35.6 billion, sharply down from the $162 billion taken in during 2013, their first year of net inflows since 2007.

Jeff Tjornehoj, head of Lipper Americas Research, said investors will have to decide if they have the stomach to stick with active funds in hopes of better results in the future.

"A year like this sorts out what kind of investor you are," he said.

Even long-time standout managers like Bill Nygren of the $17.8 billion Oakmark Fund and Jason Subotky of the $14.2 billion Yacktman Fund are lagging, at a time when advisers are growing more focused on fees.

The Oakmark fund, which is up 11.82 percent this year through Nov. 25, charges 0.95 percent of assets in annual fees, compared with 0.09 percent for the SPDR S&P 500 exchange traded fund, which mimics the S&P 500 and is up almost 14 percent this year, according to Morningstar. The Yacktman fund is up 10.2 percent over the same period and charges 0.74 percent of assets in annual fees.

The pay-for-active-performance camp argues that talented managers are worth paying for and will beat the market over investment cycles.

Rob Brown, chief investment strategist for United Capital, which has $11 billion under management and keeps about two thirds of its mutual fund holdings in active funds, estimates that good managers can add an extra 1 percent to returns over time compared with an index-only strategy.

Indeed, the top active managers have delivered. For example, $10,000 invested in the Yacktman Fund on Nov. 23, 2004, would have been worth $27,844 on Nov. 25 of this year; the same amount invested in the S&P 500 would be worth $21,649, according to Lipper.

Even so, active funds as a group tend to lag broad market indexes, though this year's underperformance is extreme. In the rout of 2008, when the S&P 500 fell 38 percent, more than half of the active large cap stock funds had declines that were greater than those of their benchmarks, Lipper found. The last time when more than half of active large cap stock managers beat their index was 2009, when the S&P 500 was up 26 percent. That year, 55 percent of these managers beat their benchmarks.