It was a startup company which I was offered equity in. Several initial expense reports were paid but then we had a show which all of the charges were on my card and they never reimbursed me before going out of business. The amount of $100,000 is well more than I am capable or willing to pay back! I would sue but I don't believe they have any money or assets!!! What can I do? Declare Bankruptcy???

Something seems odd here. You were offered equity in a company. Were you promised something that seemed way to good to be true? Did you speak to an attorney or CPA to have any paperwork signed?
It sounds more like a scam rather than a legit business.
I think you need to see an attorney right away. If it was a scam you need to file a police report. At the very least I would bet they just spent your money rather than apply it to some business venture. That could be theft by deception.
If not the attorney can try some collection efforts, try to see they have any assets, file a lawsuit, and see if there is any hope of collection.
As for BK, you can try to settle on the accounts.
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