* Jana Partners, AimCo hold more than 5 percent

* Latest move makes break-up more likely, analysts say

* Activists back in Dutch market after two-year gap

* TNT shares jump 3.9 percent, close to 2009 high

AMSTERDAM - A possible break-up of TNT moved a step closer on Tuesday as activist funds, back on the hunt for opportunities, took a 5 percent stake in the Dutch mail and logistics group.

New York-based Jana Partners and Canadian asset manager Alberta Investment Management Corp (AimCo) jointly hold the stake in Europe's second largest mail and express delivery company, regulatory filings showed.

The duo's move is seen adding to investor pressure to split TNT's lucrative express division from its troubled mail unit.

Many activist shareholders believe that value can be created by splitting up TNT into mail and express because a standalone express business would make an acquisition of TNT much easier, said ING analyst Axel Funhoff.

The credit crunch had killed off many opportunities for activist funds and also hampered their ability to invest. Their presence has not been felt in the Netherlands since ABN AMRO buyout's and breakup in 2007 was triggered by The Children's Investment (TCI) fund. The old game has started again. The funds that have bought into (TNT) ... are real break-up artists, completely not interested in the line of business, said Rob Koenders at Dutch asset management firm Harmony Vermogensbeheer, who does not hold TNT shares.

SHARES RISE ON BREAK-UP HOPES

Shares in TNT, No. 2 in Europe after Deutsche Post (DPWGn.DE), jumped in early trade to year highs and at 1220 GMT were trading at 21.15 euros, up 4 percent and outperforming the Amsterdam blue chip index .AEX, which was down 1.15 percent.

TNT's share price implies a bid for the express division at a 50 percent premium, said Kepler Capital Markets analyst Andre Mulder.

FedEx and UPS would be natural buyers, the express unit is very much a strategic asset for them. However the latest move adds to what was already there, TNT is already open to any good offer put in front of them.

A tie-up up with FedEx or UPS would challenge the dominance of Deutsche Post's (DPWGn.DE) DHL. Deutsche Post shares were down 0.71 percent to 13.31 euros.

TNT's credit default swaps widened on Tuesday, reinforcing the view that a split is now more likely. [ID:nGEE5B70TA]

The firm unveiled a restructuring plan last week dubbed 'Vision 2015', aimed at boosting profitability in its core businesses and making no reference to a possible sale.

TNT spokeswoman Daphne Andriesse declined to comment on the latest development. A Jana Partners spokesman also declined comment and a spokeswoman for AimCo did not immediately respond to an emailed request for comment outside of business hours.

Like many competitors, TNT has been struggling to cope with falling consumer demand while coming to terms with the liberalisation of the mail market.

Jana Partners and Alberta Investment jointly hold just over 5 percent of TNT, the threshold at which shareholders are required to report their stake to Dutch market authorities.

Run by former Merrill Lynch banker Barry Rosenstein, Jana Partners manages more than $2.5 billion and last year agitated for change at CNET, the U.S. web network, helping spur its eventual sale to CBS Corp (CBS.N).

The Chief Executive of AimCo, which manages C$70 billion ($66.4 billion) in government accounts and pensions in the Canadian province, said in October that the fund was looking at a half-dozen private equity deals around the world to take advantage of a recovering economy.

AimCo has a deal-value sweet spot of about C$200 million for such transactions, AimCo CEO Leo de Bever said.

Based on TNT's market capitalisation of 7.54 billion euros ($11.2 billion) as of Monday, a 5 percent stake would be worth around 380 million euros.

Before the full brunt of the credit crisis hit the mail and parcel transport sector, TNT had been the subject of speculation that U.S. rivals United Parcel Service or FedEx would make an offer as they sought a stronger European foothold.

($1 = 1.055 Canadian dollars = 0.6720 euro)

(Additional reporting by Gilbert Kreijger in Amsterdam, Quentin Webb in London; editing by Elaine Hardcastle

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