Although we don't believe in timing the market or panicking over market movements, we do like to keep an eye on big changes -- just in case they're material to our investing thesis.

What: Shares of Barnes & Noble (NYSE:BKS) took a spill today, falling as much as 16% after Liberty Media (NASDAQ:FWONA) said it sold nearly all of its stake in the ailing bookseller. 

So what: The media conglomerate has entered into an agreement to unload 90% of its holdings in a deal expected to close by April 8. Liberty had originally invested $204 million back in 2011 for preferred stock that was convertible to about 16.6% of shares outstanding and paid a dividend with a yield of 7.75%. The sale seems to reflect the flagging hopes for the Nook, Barnes & Noble's e-reader that at one point was seen as the company's savior.

Now what: With the sale, the bookseller will also lose Liberty CEO Greg Maffei from its board, a negative for the company, as Maffei is seen as a respected business leader and dealmaker. Barnes & Noble Chairman Leonard Riggio pointed out that Liberty's decision gives the bookseller "greater flexibility to pursue strategic options," as Liberty's stake had come with a right to block any assets sales, which could include selling the Nook unit or Riggio's one-time desire to take the retail business private. Still, Liberty's sale seems most reflective of the Nook's failure and the unlikeliness of Barnes & Noble returning to profitability.