The underwriters for the initial public offering have bought another $27m in shares in the Alphabet and Salesforce-backed online survey platform developer.

Sutro Biopharma, an immunotherapy developer commercialising technology created at Stanford University, has floated on the Nasdaq Global Market.

The home IoT platform floated at the foot of its range to raise almost $103m, while Xiaomi will retain a 16.4% stake in the company.

The Astra Zeneca antibiotic development spin off has floated in an initial public offering in which Novo bought more than $16m in shares.

Alexion will pay $400m upfront for Baxalta-backed Syntimmune, with up to an additional $800m on offer if the autoimmune disease drug developer hits all its milestones.

Grubhub agreed to acquire student-focused food delivery app Tapingo, which had raised $36m from investors including Qualcomm Ventures.

The online survey platform, which counted Alphabet and Salesforce as investors, floated above its range while increasing the number of shares in the IPO.

Johnson & Johnson and AstraZeneca will get a chance to exit the orphan disease therapy developer, which has filed for an $86.3m IPO.

Principia Biopharma, whose drug discovery platform is based on research at UCSF, has completed a $122m initial public offering after underwriters exercised their greenshoe option.

The Novo-backed medical implant provider has filed to raise up to $97.8m in an initial public offering that comes after $103m in funding.