(Sharecast News) - British Land said it was selling 12 superstores from its joint venture with Sainsbury's for £429m to Realty Income Corp, representing a net initial yield of 5% as the company rebalanced its portfolio.British Land's share of the proceeds will be £193.5m representing a "modest" premium to September 2018 book value, the company said on Tuesday.Net proceeds to British Land were expected to be around £95m after the repayment of debt and associated break costs."This is the latest example of how we are delivering against our clear long-term strategy to build an increasingly mixed-use business focused on three core elements: campus focused London offices; a smaller, refocused retail business and residential, principally build to rent," the company said in a statement."As part of this, we expect retail to comprise around 30% - 35% of the assets of our business, down from around half today."British Land said it expected its superstores exposure to fall to 1.3% of its portfolio based on September 2018 valuations with six standalone stores remaining.