But while reducing his stake, Helm will remain a non-executive at Bear, the startup he launched with former Innocent Drinks commercial director Giles Brook, and has been given dispensation by Mars to maintain a role in the Bear brand's marketing strategy on a limited basis.
Sales of the Bear range of adult and kids snacks is ahead of expectations, said Brook, with listings secured in Waitrose, Ocado, Whole Foods Market and Planet Organic, as well as 107 independents within the M25, with strong repeat order rates. Wholesaler Fife Creamery has been signed to help open up Scotland, while Boots will stock the range starting next month.
"The response from consumers, buyers and investors has been amazing," added Brook.
A father of four, Helm will assume marketing responsibilities for Mars' portfolio of petcare brands, comprising Pedigree, Whiskas, Sheba and Cesar.
A former marketing director at Innocent and brand controller for cereals at Nestlé, Helm said he had been impressed by Mars's £7m relaunch of Pedigree in June and aimed to replicate the "smart handling of contemporary values" with the other brands. "It is important for a brand to have clear values. That is what I learnt at Innocent and what I aim to bring to this role."
"I aim to buy a dog and bring it along too," he added.