* Dollar hits 4-month high vs yen, clears 99 mark
* Yen sold broadly as long-yen unwinding continues
* U.S. private employers shed 697,00 jobs in February
* Stocks rise, euro rebounds from 3-month low vs dollar
* Plans for more Chinese spending increase risk appetite
(Recasts, updates prices, adds quotes, details)
By Steven C. Johnson
NEW YORK (Reuters) - The dollar vaulted to a four-month high above 99 yen Wednesday as another slide in U.S. private-employer rolls and worries about a flagging Japanese economy pushed investors toward the U.S. currency.
The euro also hit a three-month trough below $1.25 but rebounded with sterling as Wall Street rallied and traders took profits ahead of more comprehensive U.S. jobs data and UK and euro zone interest rate decisions this week.
"Improved equity markets have helped sentiment today and people are taking some profits" after the dollar's recent rally brought it near or beyond important psychological levels against a number of major currencies, said David Watt, senior currency strategist at RBC Capital Markets in Toronto.
That offset data showing U.S. private employers cut 697,000 jobs last month and a separate report showing the U.S. services sector shrank again in February.
The global backdrop, though, hasn't changed, and "financial markets are still a mess, credit markets are still tight and we are still a long way from recovery," Watt said.
Midday in New York, the euro was trading at $1.2605, up 0.3 percent on the day and well off a three-month low of $1.2459 hit earlier. Sterling rose 0.6 percent to $1.4145 after dipping below $1.40.
Anxiety about the U.S. and world economies has supported the dollar in recent months as investors cut exposure to stocks and other currencies and sought safety in the greenback, which benefits from its role as the world's reserve currency.
But optimism was boosted on Wednesday partly by China, which said it would increase infrastructure and manufacturing spending, raising hopes of stimulus for the global economy.
The dollar rose to 99.48 yen, closing in on 100 for the first time since early November as investors worried about Japan's economy. It was last up 1 percent at 99.33 yen.
Bank of Japan board member Miyako Suda said on Wednesday it was hard to say whether the economy had hit bottom and voiced concerns over tumbling share prices.
"The markets have a view that Asia is going to perform just as badly maybe as Europe and the U.S. this year and there's a view that dollar/Asia en masse should go higher," said Chris Turner, head of FX research at ING in London.
Data also showed Australia's economy shrank in the fourth quarter for the first time in eight years, though hopes of increased Chinese spending helped the Australian dollar recover to $0.6484, up 1.5 percent on the day.
Analysts said the focus now shifts to Thursday's policy decisions, with the Bank of England and European Central Bank both expected to cut borrowing costs by half a percentage point to record lows.
The ECB in particular will be watched for any indication that it is considering adopting unconventional measures beyond simple rate cuts to boost the money supply and growth.
If that happens, look for renewed euro selling against the dollar, said Michael Woolfolk, senior currency strategist at The Bank of New York-Mellon.
"The market would take that to mean the ECB knows something it doesn't, and that's not encouraging," he said. (Additional reporting by Tamawa Desai in London; Editing by James Dalgleish)