Yahoo will auction 3,000 patents, which could earn it more than $1 billion, as the firm closed the second round of bidding for its core internet business earlier in the week.

According to The Wall Street Journal (WSJ), the internet giant invited potential buyers such as private equity firms and investment firms focused on intellectual property to submit bids for the patents, which include Yahoo’s original search technology.

The deadline for preliminary bids is mid-June and the auction will be run by Black Stone, a boutique investment bank.

A Yahoo spokeswoman, who confirmed a sale was being explored, said it “represents a unique opportunity for companies operating in the internet industry to acquire some of the most pioneering and foundational patents related to web search and advertising”.

In April, Yahoo assigned 2,659 patents to a subsidiary called Excalibur.

These patents cover search, e-commerce and online advertising, and also include a patent related to ad-matching technology that caused a legal dispute between Yahoo and Google in 2002.

The WSJ report quoted Maulin Shah of Envision, a law firm that specialises in patents, as saying that Alphabet and Microsoft are among the “obvious potential buyers” for the patents. The report added that prices of patent sales are “notoriously unpredictable”.

Yahoo has already earned about $600 million from patent sales and licensing fees in the past three years.

The Yahoo spokeswoman also said the firm is offering around 500 US patents and 600 US pending applications as part of the auction of its core web business.

Earlier this week, WSJ reported that Verizon bid around $3 billion for Yahoo’s internet properties. The figure may be lower than initial estimates of $4 billion to $8 billion, because Verizon’s bid does not cover the bulk of Yahoo’s most valuable patents.