Wells & Young's Brewing Company chief Paul Wells has admitted the loss of Red Stripe and Corona will have a major impact on the Bedford company.
A distribution deal with Corona ends after 15 years in January and a 30-year Red Stripe deal comes to an end in the summer.
It is understood that the two brands account for around 40 per cent of the company's annual turnover - around £85m of business. Corona has increased from an annual distribution of 150,000 bottles 15 years ago to five million today.
"Just Corona alone is quite a big chunk of our turnover and we will have to restructure the business," said Wells.
He added that it was "hard to say" if the loss of both accounts would lead to redundancies.
"There are some jobs that will transfer to the new distributor," he added.
Owner Diageo has taken back control of Red Stripe but has yet to reveal its plans for the brand. Meanwhile Corona Extra brand owner Grupo Modelo has not revealed who will be taking on distribution.
Wells added that the company could look to bring in new brands to the portfolio but would also be upping marketing around its ales and other brands such as Estrella Dam and Kirin Ichiban.
"We have got a really good portfolio of ales and those brands will get more focus.
"We are also really pleased with Estrella Dam and the response it has received in the trade."
Licensees who currently stock Corona and Red Stripe should not be affected with deals being transferred to the new distributors.
"If they are a direct customer of ours or a freetrade account then we will continue to supply the pub. If it is a national account customer in the on or off-trade then we will transfer supply to a new distributor," added Wells.