This excerpt taken from the ABII 10-K filed Mar 12, 2010.
Restricted Stock Units
At December 31, 2009, 256,705 restricted stock units were outstanding under our 2007 and 2001 Stock Incentive Plan with a weighted average per share market value of $55.29 and with vesting dates ranging from January 2010 to July 2013. Upon vesting, each restricted stock unit entitles the holder to one share of our common stock. Compensation expense related to restricted stock unit grants is based upon the market price on the date of grant and is charged to earnings on a graded amortization basis over the applicable vesting period. Restricted stock units currently granted generally vest ratably over a four year period.
Stock-based compensation costs for all RSU awards (including liability awards) for the years ended December 31, 2009, 2008 and 2007 were $9.7 million, $8.1 million, and $17.2 million, respectively. As of
December 31, 2009, there was $7.1 million of total unrecognized compensation expense related to restricted stocks granted under our stock-based compensation plans, which is expected to be recognized over a weighted average period of 1.6 years.
Following is a reconciliation of unvested restricted stock unit awards as of December 31, 2009: