By Ross Finley and Rahul Karunakar

LONDON/BENGALURU (Reuters) - Optimism about stock market performance this year has wilted, with investors fretting about the global economy and unexpected shocks likely to condemn most key indices to a weaker performance than thought just a few months ago.

The latest Reuters poll of over 250 analysts, fund managers and brokers worldwide taken June 27-July 11 also showed an intensifying pull between stretched share prices - with Wall Street at a record high - and bond markets, with most government bond yields at record lows and vast swathes of them negative.

Strategists at Citi have noted that the gap between the global government bond benchmark yield, just 0.5 percent, and the dividend yield on global equities of about 2.7 percent, is the widest in 60 years, and on that basis, stocks look attractive.

Ten of the indexes polled are expected to be lower by the end of the year when just three months ago the consensus view among forecasters was that they would be up, in some cases significantly. [Graphic: http://tmsnrt.rs/29t4c95]

But the poll results do not provide a definitive picture on where forecasters are recommending investors put their money, although hopes remain high once again that next year will be better, particularly for struggling emerging markets.

The Bank of England is set to reverse course in response to Britain's shock vote on June 23 to leave the European Union, with rate cuts and renewed government bond purchases nearly certain in an attempt to limit the damage. [BOE/INT]

The trouble is, even though the vast majority polled don't expect any financial crisis from Brexit, that shock has increased risk aversion, as well as the risk a likely British recession may have ripple effects well beyond its borders.

Expectations for an interest rate rise in the United States have also faded despite a surprisingly strong jobs report last week, triggering a rally in stocks and U.S. Treasuries.

So while in past years the prospect of more central bank cash might have lit a fire under the stock market, there is a clear sense now of pessimism in the latest results about the outlook for European shares, as well as Britain's FTSE 100. [EPOLL/FRDE] [EPOLL/GB]

"The Brexit vote has damaged the outlook for the global economy and EPS (earnings per share). This is clearly unhelpful for global equities. It also drove global bond yields down to unprecedented levels, which has increased the relative income attractions of equities," wrote Citi strategists in a note.

"These two opposing forces are likely to keep share prices trapped in the current trading range. While Citi strategists collectively forecast a 7 percent rise in global equities by mid-2017, investors could probably generate a better return if they wait for the next dip."

Even on Wall Street, where stocks had their worst start to the year ever only to rally back to a record high, in large part on optimism about the economy, many are now cautious, especially ahead of a presidential election in November. [EPOLL/US]

"It's Brexit one day, election issues the next. We've been telling clients to sort of buckle up," said Jeff Mortimer, director of investment strategy for BNY Mellon Wealth Management.

However, with increasing central bank ownership of a government bond market limited in size by fiscal restraint, stock and bond prices are likely to continue rising, simply because the money that's been created has to go somewhere.

The European Central Bank also has both feet on the accelerator, having launched its latest aggressive expansion to its stimulus well before the Brexit vote. Now many are speculating it may have to consider doing even more to make sure the euro zone economy doesn't veer off track as a result.

Perhaps unexpectedly, the most optimistic outlook appears to be for Japan, where stocks have been beaten down by a soaring yen and a moribund economy. [EPOLL/JP]

In addition to a much lengthier and more aggressive central bank stimulus program than in Europe, more fiscal stimulus is in the pipeline there after elections at the weekend where Prime Minister Shinzo Abe was victorious.

Indian shares are also expected to perform well on relative stability compared with other Asian economies, although forecasts are markedly less optimistic for the remainder of the year than those taken three months ago. [EPOLL/IN]

For Asia more widely, as well as Latin America, forecasters were less upbeat, looking past the U.S. presidential election and potential near-term trouble as a result of Brexit to peg 2017 for a rebound. [EPOLL/ASIA] [EPOLL/BR]

"There are likely to be more periodic sell-offs in risky assets in the months ahead, but we do not expect these to prevent EM (emerging market) stocks from performing reasonably well," wrote David Rees, senior markets economist at Capital Economics.

"If anything, the vote for 'Brexit' appears likely to ensure that global monetary conditions remain looser for longer," he wrote. "This, along with relatively low valuations, will support EM equities in the next 18 months."

(Poll data: <EQUITYPOLL1>)

(Other stories from the Reuters global stock markets poll:)

(Additional reporting and polling from reporters in Seoul, Shanghai, Sydney, Tokyo, London, Frankfurt, Milan, Moscow, Johannesburg, New York, Brasilia, Sao Paulo, Toronto and Bengaluru; Editing by Adrian Croft)