Bad news: there aren't any landmark cases. The area is so new that most states haven't even had this issue come up in court yet.

However, I can tell you that the general consensus is that LLCs borrow from corporate law where piercing the veil is concerned.

Veil-piercing isn't about "transacting business on behalf of the company in a role that doesn't legally exist." That's an indemnity issue (the LLC is trying to shuffle blame from itself to an employee). Veil-piercing is about going after the owners of a company on the grounds that the company is really just an extension of the owners' will and bank accounts.

Key factors for veil-piercing (for an LLC): - Owners use the LLC funds for personal expenses without reimbursing the LLC. - Zero/below-market loans from the LLC to the owners. - LLC business decisions made to benefit the owners rather than the business. - Undercapitalization (LLC not have enough money to pay its bills/expenses/liabilities without the owners covering some of these expenses).

There are more, but those are the big ones. The piggy-bank, low-interest-loan, and undercapitalization factors are usually the most important.