That was me. Didn't know system had signed me out.

You might double check the options agreement. It might read that you have to keep the stock for 9 months or they have to take backup withholding. It's unusual to require you to hold stock once you've exercised an option. In any regard, it's nice to hold the stock for a year to qualify for long term capital gains @ the 15% tax rate rather than having it treated as ordinary income.

You state that the purchase price of the stock is $20K, but your option price is "deeply discounted". I would assume then, that the value of the stock once purchased is >$20K. If it is worth $40K for example, you then would qualify for a interest only stock loan at most banks. (assuming you have good credit). Additionally, as Latitude21 stated, you will want to hold the stock for one year to get taxed at 15% as opposed to ordinary income tax rates. For example, if the pruchase price is $20K and the stock is worth $40K and your fed tax rate was 35%, you would pay $7K in taxes if sold within one year. If you held it for one year, your fed tax would be $3K. (15% of 20K profit) Here's a link to some good info on stock options from a tax perspective: http://www.turbotax.com/articles/IncentiveStockOptions.html

Lastly, be sure to file a IRS form 6251 if you buy and hold. You can find info on this in the above link.