SAN FRANCISCO ( TheStreet) -- Twitter's valuation is jumping following a new investment offer from BlackRock ( BLK), according to published media reports. Citing anonymous sources, the Financial Times late Friday reported that BlackRock had launched an $80 million tender offer to a number of Twitter's early employees. The offer would value the social media company at more than $9 billion, up from the $8 billion valuation at the time of Twitter's last significant round of fundraising, the newspaper said. The latest valuation is less, however, than the $10 billion to $11 billion price implied by two secondary transactions completed last year, the FT added. The FT said that although Twitter facilitated the transaction, it did not raise any new capital with it. Also citing anonymous sources, The Wall Street Journal later reported that BlackRock had made a tender offer of about $80 million. Both BlackRock and Twitter declined to comment, the FT reported. Shares of BlackRock finished Friday up 9 cents at $236.42.