According to The Sunday Times, Brains, led by chief executive Alistair Darby, has hired advisers from Evercore to invite offers for an investment or sale to a trade buyer.
The Cardiff-based brewer has been owned by the same family since it was founded in 1882.
In March this year, prior to the onset of the pandemic, Brains said it would sell 40 of its 200 pubs to pay off debts and help it to navigate 'uncertain economic times' created by Brexit and rising wage costs.
Meanwhile, earlier this month Darby announced that the pubco was to temporarily close more than 100 of its managed pubs in response to Wales' new Coronavirus restrictions that ban the sale of alcohol in pubs and restaurants.
Already facing costs of £1.6m on the back of the country's recent firebreak lockdown, Darby described the rules as a “closure by stealth” and called on politicians to “stop changing their mind” on what is required.
“It’s hugely frustrating and a bit insulting,” he said.
“It says people are not making the effort being asked of them.
“The sector has done more than its fair share to ensure those potential deaths are avoided."
Last Friday, the Welsh First Minister Mark Drakeford warned that the country will go into full lockdown after Christmas if Coronavirus case numbers fail to drop.