Hong Kong fund leads chase for Germany energy management group Ista -sources

* CKI submits binding offer of more than 4.5 bln euros -sources

* Sources say CPPIB/Blackstone (NYSE: BX - news) and OTPP/Brookfield not bidding

* Owner CVC expected to decide on buyer this week -sources (Adds detail on Ista, CKI, valuation)

By Arno Schuetze and Claire Ruckin

FRANKFURT/LONDON, July 25 (Reuters) - Hong Kong's CK Infrastructure(CKI) is seen as the frontrunner to buy German metering and energy management group Ista for more than 4.5 billion euros ($5.2 billion), sources close to the matter told Reuters.

CKI, part of ports-to-telecoms conglomerate CK Hutchison , made a binding offer for private equity-owned Ista on Tuesday, the sources said, adding that two consortiums considered strong contenders refrained from making final bids.

It remains unclear whether other final bids were submitted, they added.

Canada Pension Plan Investment Board, which already owns a minority stake in Ista and had tied up with Blackstone to buy the whole company, was one of the contenders to hold back, as was a consortium of Ontario Teachers' Pension Plan and Brookfield.

Owner CVC is expected to choose a buyer this week, two of the sources said.

Buyout group CVC (Taiwan OTC: 4744.TWO - news) , which bought Ista in 2013 at a valuation of 3.1 billion euros, had hoped to fetch up to 5 billion euros for Ista, equating to 12 times expected 2017 core profit (EBITDA) of 420 million euros, people familiar with the matter said last month.

CVC declined to comment on Tuesday and a CKI representative was not immediately available for comment. The other investors declined to comment or were not immediately available.

Ista, which provides energy and water metering, posted EBITDA of 370 million euros in 2016 on sales of 850 million euros.

CKI has a market capitalisation of HK$190 billion ($24 billion) and is invested in electricity generation and distribution, gas distribution, oil pipelines, water supply and wind power.

Its European investments include a slew of British assets such as UK Power Networks, one of the largest electricity suppliers to London, as well as water, sewage and even rolling stock group UK Rail.

It also owns the Netherlands' largest energy-from-waste company AVR and has interests in Portugal Renewable Energy. But so far it lists no German investments on its home page.

The deal is being closely watched by investors ahead the planned sale of Ista peer Techem by Australian infrastructure investor Macquarie in the autumn, sources have said.

European bankers are working on debt financing in excess of seven times Ista's EBITDA and some bankers are working on leverage levels as high as 8.5 times, banking sources said.

CVC's adviser, Goldman Sachs (NYSE: GS-PB - news) , is offering staple financing of about 5.8 times, significantly lower than European banks, to comply with U.S. guidelines on leveraged lending.

Hoping to attract sponsors, the staple is a hybrid facility that would allow dividend payments, the sources said. ($1 = 0.8584 euros) ($1 = 7.8074 Hong Kong dollars) (Additional reporting by Alexander Hübner and Dasha Afanasieva; Editing by Maria Sheahan and David Goodman)