MUNICH, March 12 (Reuters) - Volkswagen will

make the sale of a majority stake in its Everllence subsidiary

contingent on holding company Porsche SE becoming a

co-investor of about 10% in the maker of large marine engines,

two sources familiar with the matter told Reuters.

While VW has for months been seeking competing bids for

Everllence, it has not been previously reported that Porsche SE

- the Piech and Porsche families' investment vehicle that

controls the VW group - would be a shoo-in for a smaller stake.

Six financial investors have advanced to the second stage of

bidding for 51% of the shares after making offers that value all

of the maker of large diesel engines and industrial heat pumps

at about 8 billion euros ($9.25 billion), the people said.

A deal is expected by summer, they added.

VW and Porsche SE declined to comment.

($1 = 0.8653 euros)

(Writing by Ludwig Burger, Editing by Miranda Murray)