* Questions over Greek buyback keep investors cautious
* Technical charts hint at rise to Bund range high
* Peripheral rally stalls, investor sentiment split
By William James
LONDON, Nov 30 (Reuters) - German Bund futures held firm within sight of recent highs on Friday after a turbulent week of trading with investors cautious over how a deal that saw aid funds released to Greece would be implemented.
The deal, agreed earlier this week between euro zone finance ministers and the International Monetary Fund, had dented the appeal of Bunds. But doubts about the plan quickly resurfaced and highly liquid German debt, to which investors turn in time of stress, recovered losses.
The Bund futures contract was four ticks higher on the day at 142.88, closer to the Nov. 13 high of 143.48 than the bottom of the recent range marked on Tuesday at 141.84.
"This reflects the fact that to a certain degree the market is not convinced about that deal," said Christian Lenk, fixed income analyst at DZ Bank in Frankfurt.
Questions centred on the proposal to buy back a portion of Greek debt, with a lack of clarity about how the operation will be funded, and how repurchase prices will be decided, keeping investors on edge.
"Uncertainty around eventual take-up at this reverse operation and the prospect of 'holdouts' again complicating the picture risk another unwelcome flare-up in market tensions," Lloyds Bank strategists said in a note to clients.
"This backdrop should prove sufficient to attract funds back into core product at higher yield levels, thus effectively providing a near-term cap to core fixed income rates."
Technical charts showed support for Bund futures at 142.62, the mid-point of Tuesday's steep sell-off and a shift in momentum towards fresh rises.
"As long as 142.62 is support we're happy bulls and expecting an assault on 143.48," said Futurestechs technical analyst Clive Lambert.
Spanish and Italian 10-year bond yields were also stable in early trading at 5.36 percent and 4.54 percent respectively.
Investors hungry for higher yielding debt have piled into the euro zone's peripheral markets this week, pushing Italian 10-year yields briefly to a two-year low, but after such sharp moves traders saw limited room for a further rally on Friday.
"Yesterday morning (peripheral debt) went off to a flyer and then gave it all back in the afternoon. It's had a good week but I still don't think we're out of the woods," a trader said.
The risk that the U.S. economy could slip into recession if lawmakers fail to find a way around $600 billion of automatic spending cuts and tax hikes due early next year was also a limiting factor for peripheral debt, the trader said.
The U.S. "fiscal cliff" problem, along with concerns over the health of Spain's economy, was likely to keep euro zone markets in their current unusual state -- where both low-risk and high-risk assets are in high demand.
"Everybody is a little bit split. You want to be in the rally in the periphery but on the other hand you don't want to get completely out of your safe haven," Lenk said.