Shake Shack is up 12% for no reason

Shake Shack shares are up 12% for no reason.

On Friday, the burger chain was rally after declining about 5% on Thursday.

On Wednesday, however, the stop was up 20%.

Wednesday also marked the end of the company's lock-up expiration period, which allowed some company insiders to sell their shares for the first time.

The company is set to report earnings on August 10.

At the current share price, Shake Shack is worth about $2.5 billion.

Here's the stock chart of the last 3 days...

...and the chart since the company's public debut in January.