Summary List PlacementWhen Melissa Zhang's visa was about to expire, and even her powerful employer BlackRock could not help her renew it, she packed up her San Francisco apartment. Right before leaving the country, she was reprieved: her manager told her she'd won a visa lottery on the third attempt. Now Zhang is working on a business degree at Stanford and wants to found a clean-energy startup. But she's not sure that she'll be allowed to remain in the US long enough to do so here.