to pay off debt?? sure. of course they must but please, folks, do the math!
net proceeds will be about 200 million after costs. at the same time if they intend to keep the dividend they will need to pay out an extra 13,2 million $ a year in divys. That is roughly equal to their current blended interest rate (cost) but their future one will likely be much higher given the falling and doubtful value of their properties.
price/book after that highly dilutive offering will jump to more than 1.4.

Now: do you really want to own a business that
- doesn't even generate enough cash to service its existing debt,
- owns properties many of which were bought at the peak of the RE bubble and where you pay 1.4 times book for these overvalued properties!
- is dependent on rich daddy continuing to spend for his spoiled son or spoiled daughter while the economy continues to shrink and while incomes will keep declining even in a stagnant economy

???
really, then go ahead.
ACC is a terrific short here and of course I will hedge that short by going long some high quality reits (which ACC is definitely not)
aand those who take comfort in the fact that the dilutive offering didn't cause the stock to crash - don't worry. other reits shot up to the moon at the same time and when the current bullish exuberrance cools down the market will start differentiating a lot over the coming months between the good the bad an the ugly companies.
acc will at best be dead money for years to come, but much more likely will go down big over the next 1-2 years