Square CEO Jack Dorsey announced via his Twitter account that his mobile point-of-sale startup has landed a new round of investment worth $100 million. According to the Wall Street Journal this round of financing was led by venture capital firm Kleiner Perkins Caulfield & Byers (KPCB). The Journal reports the official announcement of the funding could come as soon as Wednesday.

Dorsey also mentioned in his tweet that Mary Meeker from KPCB will be joining Square's board. Square has recently added former White House advisor Larry Summers and technology giant Vinod Khosla to its board.

The Journal reports the official announcement of this funding could come as soon as Wednesday.This is just the latest round of big money Square has secured in the past few months. The company announced $27.5 million in Series B funding in January. Payment processor Visa invested an undisclosed sum in the "low single digit millions" in April. According to the Journal, the most recent funding puts Square’s valuation at more than $1 billion.

While Square continues to attract investors, and plenty of press, the Journal quotes Forrester researcher Sucharita Mulpuru warning the company may be overvalued. "(Square’s) valuation is highly speculative and indicative of the bubble we're in," Mulpuru said in the article. “Established players want a crack at this, and could render the device and the company irrelevant."