Online storage startup Dropbox is about to raise a fresh round of funding that could value the company at a shocking $10 billion, MG Siegler at TechCrunch reports.

Dropbox has a collection of term sheets from a number of investors and it just has to pick who it wants. At least one term sheet has the $10 billion valuation, but a source tells Siegler the valuation will probably settle closer to $5 billion.

Think about that: At least one investor thinks the company is going to exit at $50 billion, assuming the investor is factoring in a 5X return on money. That's a pretty big vote of confidence.

Dropbox is looking to raise $200-$300 million, which would be its first really big raise of money. It raised $7 million in 2007.

This could be one of the last mega-funding events we see for a while. The economy is quickly heading south and at least one VC is publicly warning startups that it could get rough out there for raising money.