What happened 

Today started with what appears to be a big loss for IAC/InterActiveCorp. (IAC -3.24%) with the stock falling as much as 37.1% from its closing price yesterday. And depending on where you're checking stock prices, that might be what you're seeing in the market. But that's not the full picture.

IAC has spun off Vimeo (NASDAQ:VMEO), which officially started trading today, and now IAC shareholders own shares of IAC and Vimeo. And it's both of these stocks together that investors should be focused on. 

IPO spelled with blocks.

Image source: Getty Images.

So what

Vimeo's shares have been trading for about a week on what's known as a "when issued" basis, meaning shares are trading but hadn't officially been issued yet. In that respect, they aren't brand new to the market today like a traditional IPO, but this is the first day IAC shareholders get the stock.

IAC shareholders received 1.6235 Vimeo shares for each IAC share in the spinoff, which essentially peeled off value that was in IAC shares yesterday. To get a true picture of what IAC shareholders gained or lost today, we need to add the value of an IAC share and 1.6235 Vimeo shares together. As I'm writing, that value is $245.27 per share, or slightly below the $252.63 IAC closed at on an unadjusted basis yesterday. 

Now what

There's really nothing to panic over in today's stock moves. If you were an IAC shareholder, you now own shares of IAC as well as Vimeo. The only question is whether selling one makes sense for you now that they're separate companies. Vimeo is now a pure play in streaming video and will need to stand on its own as a newly traded public company.