Confirmed: Dropbox is raising a huge round, and it’s even bigger than the rumors

Dropbox has a lot of new cash in its war chest.

The cloud storage company has raised $325 million in venture funding over the last several months — and it appears to be aiming for an even higher total. It filed a Form D with the SEC on Monday that pegs its full offering at $450 million. (See the filing below.)

A report last month suggested Dropbox had secured $250 million in new funding, which would value the company at close to $10 billion. That funding is part of Dropbox’s $450 million offering, which has clearly grown as it’s secured additional commitments.

In addition to the $325 million from institutional investors, Dropbox has secured $25 million from “strategic investors,” a person familiar with the situation told VentureBeat. Because those investments are technically still pending, they’re not reflected in Dropbox’s SEC filing.

Dropbox is jousting with key competitor Box to become the dominant cloud storage provider for enterprises. Earlier this month, Dropbox hired former Motorola CEO Dennis Woodside as its first chief operating officer to help lead the charge into the enterprise.

Dropbox has more than four million businesses using its service, according to the company. Box is much smaller — it hit the 200,000-business mark in December — but Dropbox is wary of losing customers to Box, which has a stellar reputation for its ease of use and tight security.

Industry observers expect Dropbox to go public this year, though this massive private financing may forestall IPO plans for some time. BlackRock is reportedly leading the current financing. Other Dropbox investors include Goldman Sachs, Sequoia Capital, Index Ventures, and Accel Partners.

Updated at 12:30 PM PST with additional details