Ocado shares broke through its 180p float price this morning for the first time since early 2011.

The shares rose 9% to 185p in early trading, adding to yesterday’s 24% gain, which was sparked by news that the online grocer was in talks with Morrisons.

The discussions could lead to Ocado giving Morrisons access to its technology and warehouses so the Bradford-based supermarket can kick-start the launch of an online service.

Ocado shares have more than doubled from 60p in four months, boosted also by the appointment of former M&S boss Sir Stuart Rose as chairman and a major refinancing deal.

After the IPO in 2010, Ocado briefly traded above the float price in the first half of 2011. However, it has traded well below that level for much of the last two years.

Some analysts remain unconvinced by the latest surge in the shares. “News of a potential joint venture with Morrisons might help CFC2 economics, but tells us that Ocado will struggle to use its new capacity productively,” said Panmure analyst and long-term critic Philip Dorgan.

CFC2, the company’s second distribution centre, is located in Dorden, Warwickshire and opened in February.