* Interested parties include First State, Enovos-sources
* Indicative bids due by April 4 -sources
* Thyssengas enterprise value seen at 500-550 mln euros (Adds quote from source, additional information)
By Christoph Steitz and Arno Schuetze
FRANKFURT, March 24 (Reuters) - Macquarie-owned MGX.AX German gas grid Thyssengas is attracting interest from several infrastructure funds and financial investors, two people familiar with the matter said, adding bidders had until after Easter to submit indicative offers.
"The level of interest is huge, there's a run on regulated energy infrastructure," one of the people said, adding due diligence, which gives potential buyers access to the target's books and data, was expected to start in mid-April.
Power and gas grids are among the most sought-after infrastructure assets, giving investors stable returns on their investments of as much as 9 percent at a time when key interest rates in Europe have fallen to zero. expected to submit indicative bids by April 4 include: First State Investments, the asset management unit of Commonwealth Bank of Australia (CBA) CBA.AX ; Borealis Infrastructure, part of Canadian pension fund OMERS; Luxembourg-based power firm Enovos International SA ENVIL.UL ; Belgium's Fluxys FLUX.BR ; and Australia's Hastings Funds Management, the people said.
One of the sources added that interest was also likely to come from local utilities and German insurers, not mentioning any specific names.
Macquarie, Borealis, Enovos, Fluxys and First State all declined to comment. Hastings was not immediately available for comment.
Thyssengas, which operates a 4,200 km underground network and employs 270 staff, transports up to 10 billion cubic metres of natural gas per year. Its enterprise value, which includes debt, is seen at 500 million to 550 million euros ($558 million to $614 million).
The sale of Thyssengas, which Macquarie acquired from German utility RWE RWEG.DE in 2011, is managed by Bank of America Merrill Lynch (NYSE:BAC) BAC.N . ($1 = 0.8961 euros) (Editing by Ludwig Burger and Keith Weir)