Great Portland Estates' strong start to the year reinforces the strength of its portfolio, Jefferies analysts say in a research note. The British property developer's new leases and renewals were signed at rents above estimated market values, reflecting continued demand for the company's prime office and retail properties, the analysts say. The company's offering for fully managed offices is the main growth driver, with strong pricing and leasing momentum across several key developments, they say. Additional space currently under offer at even higher rents further supports their positive view, they add. Shares trade 0.5% higher at 335 pence. (nina.kienle@wsj.com)