I thought this one was interesting, Bloomberg:

MBIA Inc.'s credit rating downgrade by Moody's Investors Service is likely to trigger $7.4 billion of payments and collateral postings.

The company's stock dropped 13 percent on June 20 after Moody's reduced MBIA's insurance financial strength rating five levels to A2 from Aaa. Armonk, New York-based MBIA issued a statement June 20 saying it had $15.2 billion of assets to meet the posting requirements