Staff at Superquinn have been told that there will be no change to their terms and conditions, or their pensions, under the takeover by Musgraves.
2,800 people work at the chain, which went into receivership last night.
However, the Musgrave group, which is third in the market, has confirmed it wants to takeover 23 Superquinn stores and retain the workforce.
The takeover will have to be approved by the Competition Authority before it can be finalised.
CEO of Superquinn Andrew Street says staff concerns are now allayed.
"I think staff are very relieved to know that there jobs and pensions are safe," said Mr Street.
"Their future prospects are safe in the hands of Musgrave. I think there was a bit of concern last night when the word 'receivership' was banded about.
"I'm confident that, this morning, we've allayed a lot of those concerns."