LONDON (Reuters) - Private equity-backed cyber security firm Avast [IPO-AVAS.L] is set to price its initial public offering at 250 pence a share, a bookrunner source on the deal said on Wednesday, at the bottom of a 250-270 pence price range set earlier.

The logo of Avast Software company is seen at its headquarters in Prague, Czech Republic, April 12, 2018. REUTERS/David W Cerny

The company aims to sell around 25 percent of its stock and raise up to $200 million in proceeds in what is expected to be one of Britain’s biggest ever technology IPOs.

Based on the latest price guidance, Avast would achieve a market capitalization of 2.5 billion pounds upon listing.

The market admission will take place on Thursday, one of the bookrunners said, adding that books for the offering have been covered multiple times.

Avast is 46 percent-owned by its founders, Czech entrepreneurs Pavel Baudis and Eduard Kucera. CVC Capital Partners [CVC.UL] has a 29 percent stake, with Summit Partners holding 7 percent.

The security software services provider had already planned a U.S. IPO in 2012 before backtracking citing market conditions.

The listing is expected to be the biggest by market capitalization in London since July when the flotation of Russian gold company Polyus gave it a 6.3 billion pound market value.

In 2017, Avast’s adjusted revenue was $780 million and adjusted cash earnings before interest, tax, depreciation and amortization (EBITDA) was $451 million.

With net debt of around $1.35 billion, the enterprise value of the company could be up to $5.9 billion after the offering.

($1 = 0.7399 pounds)