Raspberry Pi, the maker of DIY computer kits, has seen its shares jump more than 40% three days before it is available for retail investors to trade.
Shares have begun "conditional dealing" allowing institutional investors to submit orders ahead of full trading on Friday.
Originally priced at 280p, as confirmed this morning, shares in the DIY computer maker lifted to 392p.
It means the company will list with a market capitalisation of more than £540 million, with over 45.9 million shares set to be sold by the Cambridge firm.
A further 2.1 million shares will be offloaded by existing shareholders of the company, while 11.2 million new shares will be issued, raising around £31.4 million.
In total, the offer size is around £166 million and represents a little over 30% of the total ordinary shares in admission.
A further 3% of shares are being held by the company and will be made available should an "over-allotment" option be exercised, bringing the total raised to £179 million.
The IPO, which was confirmed last month, is being 'cornerstoned' by Lansdown Partners and Arm Technology Investments (whose parent company, the British semiconductor giant Arm Holdings PLC, provides Raspberry Pi’s processing units).
Raspberry Pi’s listing is being hyped as a shot in the arm for the London Stock Exchange.
Last year was one of the worst years for London IPOs on record, as companies skirted the capital markets amid soaring inflation and sky-high interest rates.
Added conditional dealing updates