Leece will oversee the creation of new data products and services.
The group had been expected to hire about 2,000 new employees.
The S4 Capital founder spoke at Campaign's Breakfast Briefing this morning.
Apple has beaten Google to the top, with Amazon in third place.
Sir Elton John is to replace Mr Bean as the face of Snickers' ongoing "You're not you when you're hungry" campaign in a new hip-hop-themed ad.
Mars has consolidated its estimated $1.8bn (£1.4bn) global media planning and buying business into Group M's MediaCom, following a six-month review.
Samsung has appointed Leo Burnett as lead agency for its global Visual Display business, starting with a brief to create work for the Korean tech brand's QLED TVs.
Unilever is trialling a new agency model which will see creative agency talent within a holding group integrated into a single team.
McCann London has scooped the Creative eCommerce Lions Grand Prix at Cannes for its campaign for Microsoft encouraging gamers to design and share their own controllers.
Keith Weed has reaffirmed Unilever's commitment to purpose-driven marketing at a Cannes Lions session featuring founders of three of the company's brands.
Initiative's global chief executive Mat Baxter on the agency's fightback in 2017, why he welcomes competition from the consultancies, and a crucial 12 months for the UK business.
Bozoma Saint John, the newly-appointed chief marketing officer at talent agency Endeavor, has urged women to make proactive salary demands to ensure they receive the same remuneration as male colleagues.
Sir Martin Sorrell has confirmed details of his return to the front line of advertising only weeks after leaving WPP, with the launch of a new "multinational communication services business".
Facebook has suspended around 200 apps from its platform, as part of an investigation into the misuses of data carried out by Cambridge Analytica.
For all the talk about 'legacy', industry experts are struggling to agree on how Sir Martin Sorrell will be remembered in years to come.
WPP-owned research and insight specialist Kantar is launching a new Analytics Practice, amid rumours that the holding group may be preparing to sell the division.
Procter & Gamble chief brand officer Marc Pritchard is to chair a new CMO Growth Council, backed by Cannes Lions and the Association of National Advertisers.
Controversy around Sir Martin Sorrell's pay and management of the company have resulted in a succession of negative stories about WPP.
Facebook founder Mark Zuckerberg has been summoned to appear before UK politicians amid concerns about the use of its data by Cambridge Analytica.
MediaCom is looking to ensure greater consistency across its network with the appointment of Kate Rowlinson as managing director of its Worldwide Hubs.