The former Frasers Group chief executive bought the shares in his name, rather than via a company, suggesting the deal is a personal bet on the prospects for Grainger and the build-to-rent sector.
The present CEO will step down by the end of the year after 18 years with the build-to-rent specialist.
In these uncertain times, few sectors can offer the same combination of yield, security and scalability.
Revenue fell 22.8% year on year in the year to the end of September, but the group highlighted over £340m in contractually secured revenue for the ahead year.
The plans include five new buildings with 1,452 homes homes split across build-to-rent, co-living and student accommodation.
The developer plans to add a further 541 homes across three towers in the second phase of its scheme in the South Bank regeneration area.
The portfolio has around 1,400 homes spread across 18 sites outside London worth a total of more than £400m.
The BTR specialist's pre-tax profits leapt 153% year on year to £102.6m in the year to the end of September.
Heim is funding the 11-storey, 456-home scheme with McLaren acting as development partner.
Investec and Bank of Ireland financed the scheme, which will have a £145m gross development value.
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