* Swiss operator Six submitted highest Borsa bid -sources
* Euronext and Deutsche Boerse have also made bids
* Bids value Borsa at 3.5-4 billion euros -sources
* LSE selling as part of Refinitiv bid antitrust remedy
(Adds context, financial details)
By Elvira Pollina, Pamela Barbaglia and Francesca Landini
MILAN/LONDON, Sept 14 (Reuters) - Switzerland's Six has made
the highest bid in the battle for Borsa Italiana, ahead of
France's Euronext and Deutsche Boerse, two
sources familiar with the matter said.
The indicative bids valued the Milan stock exchange operator
at around 3.5 billion euros to 4 billion euros ($4.15-$4.74
billion), one of the sources said, with Six leading the race.
The London Stock Exchange (LSE), which took control
of Borsa in 2007 for 1.6 billion euros, is now trying to sell it
as part of the regulatory remedies to clear its $27 billion
acquisition of data provider Refinitiv.
Refinitiv is 45% owned by Thomson Reuters,
which is the parent company of Reuters News.
The move has put Borsa Italiana at the centre of another
shake-up in the European exchange sector after Six became
Europe's third-largest operator by revenue this year following
its 2.57 billion euro takeover of Spanish rival BME.
LSE and Six declined to comment.
The bids are still non-binding and will need to go through
an in-depth review by the LSE, a third source said.
"It's too early to draw conclusions. Execution remains a key
factor, it's not just about price," this source said, pointing
to possible interference from Rome, where politicians want to
retain a say over Borsa's strategy and management.
Another source said Six is open to discussing its governance
with Italian authorities and is looking to use BME's takeover as
a blueprint for the deal.
But it has no plans to team up with an Italian or eurozone
partner since its offer is fully funded, the source added.
DIGITAL UPGRADE
Six, which reported 7.260 billion Swiss francs in cash and
cash equivalents in the first six months of the year, has
offered to invest in the digital upgrade of Borsa as part of its
bid, a fifth source said, adding Borsa would face less pressure
as part of an unlisted group.
French exchange Euronext said on Monday it had submitted a
non-binding offer and was teaming up with Italy's Cassa Depositi
e Prestiti (CDP) and Intesa Sanpaolo.
But unlike Six, Euronext would need to raise cash as its
balance sheet is more stretched, Jefferies analysts said.
Euronext told investors during its second quarter results
that its liquidity, including an undrawn revolving credit
facility, stood at 1 billion euros.
Rome is keen to see Euronext prevail and Italian Finance
Minister Roberto Gualtieri met privately with the French
exchange's boss Stephane Boujnah in Rome last week.
Germany's Deutsche Boerse has also bid for Borsa as it seeks
to expand across Europe after failing to merge with the LSE in
2017.
Deutsche Boerse said last year that it had 2 billion euros
available for mergers and acquisitions.
(Reporting by Elvira Pollina, Pamela Barbaglia and Francesca
Landini; Additional reporting by Dominique Vidalon, Tom Sims and
Maya Nikolaeva; Editing by Jason Neely, Susan Fenton and
Alexander Smith)