Eagle Envelopes, on the WS2 Industrial Estate in Bloxwich Road, had been running since 1985.
It is part of the German Mayer-Kuvert Network and was merged in December last year with Heritage Envelopes, in Blackburn, to create a combined business with turnover of nearly £20 million.
At the time it was said at the time that the Eagle site would be retained as the stock site and for overprinting.
Heritage said the deal would strengthen its position in the UK market and enable it to further invest and encourage further growth and development for the future.
The combined Heritage business had 120 workers in Lancashire involved in envelope and paper bag manufacturing, with 10 at Walsall.
The eight remaining staff at Walsall have now been told that the site will close on May 31.
Director Phil Bryan said consultation over redundancies was nearing completion.
Eagle was involved in distributing 300 million envelopes annually, supplying the mailing industry, print trade and paper and office products distributors.
Operations will be centralised at Heritage's headquarters in Blackburn. It is one of the biggest envelope manufacturers in the UK, with 14 machines
Mr Bryan said: "The envelope industry has been hit hard by Covid and there has been a severe paper shortage in the envelope industry for five months due to a mill strike in Europe.
"The shortage of envelope reels has forced the price sky high - since April last year the price is up 70 per cent".
Mr Bryan said that a new occupier had been found for the Walsall site. It was not part of the Mayer-Kuvert Network, which is made up of 30 companies in 16 countries and employs 1,700 worldwide.