* Buys 12.65 pct stake in Ziggo for 632.5 mln euros
* Liberty already present in Netherlands through UPC
* Ziggo shares rise on speculation of full takeover bid
* Liberty already tied up with $15.75 bln Virgin Media deal (Adds shares, analyst comment, background)
AMSTERDAM, March 28 (Reuters) - Cable operator LibertyGlobal extended its reach into the Netherlands bybuying a 12.65 percent stake in Ziggo for 632.5million euros ($808 million), prompting speculation it mighteventually make a full bid.
Liberty Global, which owns Dutch cable firm UPC, said onThursday it bought the shares in the Netherlands' largest cableoperator for 25 euros apiece from Barclays Capital Securities.
Barclays ended up with a 14.2 percent stake in Ziggo afterfailing to find enough buyers for the shares in a sale it ranlast week.
Ziggo shares shot up 9.3 percent to 26.565 euros in earlytrading, valuing the whole company at about 5.3 billion euros.
Analysts said the rise was based on the idea Liberty couldmake a full bid, although they added it probably couldn't in theshort term because it was already planning to buy Britain'sVirgin Media Inc for about $15.75 billion.
"Ziggo shares should benefit from hopes of an eventualtakeover by Liberty, but we think the shares are also seeing ashort-squeeze following overhang from the recent placing," saidUBS Investment Research in a research note.
Liberty said in a statement the acquisition, in a sector inwhich it is already involved, was attractive given the stock'sdividend yield of about 7.4 percent, based on the expectationthat Ziggo would pay 370 million euros to investors in 2013.
Liberty said it would fund the purchase with a non-recoursemargin loan and existing cash.
Ziggo serves around 2.8 million households in theNetherlands, with almost 1.8 million Internet subscribers, morethan 2.2 million subscribers using digital television and 1.5million using its telephone service.
UPC has 1.7 million Dutch customers of its Internetservices, with just over 1 million people using either itsdigital or Internet services and more than 900,000 telephonysubscribers.
($1 = 0.7824 euros) (Reporting by Gilbert Kreijger and Philip Blenkinsop;additional reporting by Leila Abboud; Editing by Sara Webb andMark Potter)