After proposing that Target's real estate gets folded into a REIT and getting rejected, Pershing Square Capital Management has now turned its sights to General Growth Properties.The website-less fund, managed by William Ackman, has now apparently acquired a 20% interest in the mall owner. In a Bloomberg article, Merrill Lynch analysts say it "is the first sign that any investor has expressed a strong interest in the company or sees significant value beyond the mountain of debt." We're certainly not investment experts by any means, but doesn't it seem kind of funky? Kind of like reaching for straws? Or does it just make sense to buy up shares of a company trading under $1 that has real estate theoretically valued in the many billions?We were recently in Boston, staying near GGP's Faneuil Hall Market Place, and even though the weather was akin to Antarctica's, plenty of people were milling about and filling the restaurants on weekday evenings. It's probably not the most scientific example, but it made us think that this portfolio has to be worth something to someone.