THe FT says it well.

More news that Greece will get bailed out. For the umpteenth time. That is no surprise, but the market rallies and sells-off sloppy near the close. You will probably also read news about investor sentiment being overwhelming bearish.  Analogous to that, some of you might recall my mentioning yesterday that September expiration index options appeared much more loaded on the put side and to expect fireworks. We did have them today and that will continue.

The Financial Times summed it up well: “Apparently stocks rallied on the news, but we have no idea why, and we’re tired of guessing.”