J.P. Morgan Chase is in talks to take a minority stake in Twitter that would value the microblogging site at $4.5 billion, according to published reports.

The investment firm's new $1.2 billion Digital Growth Fund is leading the effort, however exact terms of a possible investment are unknown, according to reports by The Wall Street Journal and The New York Times that cited people familiar with the matter. They cautioned that talks are continuing and there is no guarantee an agreement will be reached.

Twitter representatives did not immediately respond to a request for comment.

The fund, which is expected to focus on private Internet and digital-media companies, is also said to be interested in investing in online gaming giant Zynga and group coupons site LivingSocial, according to the reports.

Twitter completed a $200 million funding round in December--led by investment firm Kleiner Perkins Caulfield & Byers--that gave the company at a $3.7 billion valuation. The funding was expected to be use to ramp up engineering resources to support a growing user base and allow early employees to cash out some company stock.

The talks come on the heels of Facebook's $500 million funding round through deals with investor Goldman Sachs and Russian investment firm Digital Sky Technologies that gave the social-networking giant a valuation of $50 billion.

Twitter, which limits its users to 140-character broadcast messages, has been credited with playing a pivotal role in the civil unrest that led to the resignation of Egyptian president Hosni Mubarak.