Yahoo has launched an auction in which it plans to offload 3,000 or so patents. The pioneering Internet company hopes to secure more than $1 billion for the portfolio according to sources familiar with the matter as reported by The Wall Street Journal.

The Marissa Mayer-led company has reportedly sent courting letters to a range of potential buyers over the past several weeks. Some of the patents on the auction block are decades-old, one person said, dating back to Yahoo's initial public offering in 1996. The bundle even encompasses Yahoo's original search technology.

Sources say Yahoo has hired boutique investment bank Black Stone IP to run the auction and has set a mid-June deadline for preliminary bids.

A Yahoo spokesperson confirmed the auction with the Journal, saying 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.

The auction comes at a time when Yahoo is auctioning off its core web business. Sources tell the publication that Verizon put in a bid of around $3 billion before the Monday deadline for second-round bids although the bulk of Yahoo's most valuable patents weren't included in the bid.

The auction for its core web business, a Yahoo spokesperson said, includes a smaller group of about 500 patents and more than 600 pending applications. The smaller bundle is said to be instrumental to running Yahoo's core web business.

Marissa Mayer image courtesy Bloomberg News