Maybe this is a stupid question but is a -294% tax rate the same thing as a 0% tax rate?
No, it means you get 294% more back from the government than you paid in taxes. Such things are not uncommon at the low end of the income scale, but much rarer at the higher end.
I don't think it's usually that simple. What usually happens is it's allowed to be applied to future taxes. Trump himself had a thing go on similarly in the past. He "lost" a billion dollars through some business deals and then simply didn't pay taxes for the next few years because he was able to roll over his "losses" into the next years. That can go on for several years, but I think there is a limit. With a company like Mylan though I'm sure they've planned it out and have something new ready and waiting.
The other thing that Trump took advantage of was bankruptcy laws. When a company goes bankrupt its the company that loses things not the people involved... even if in practice the company's finances are closely tied to the owner. Trump in particular got a lot forgiven in one of his bankruptcy dealings including getting to stay on as CEO and that's where his "bankruptcy laws have been very kind to me" quote comes from.
US law really is fucked up right now in terms of finances. Small business laws can be exploited to simply go bankrupt instead of paying your employees, then start a similar new business (possibly even under a shell corporation that owned the first one). So you can graduate college with a bunch of private student loans, get a job, not get paid even tho you did the work, then you go bankrupt and your debt is almost entirely not forgiven. While the guy who didn't pay you still has the same amount of money as before since he had almost no assets in the business. And absolutely none of that is illegal. Nor will your debt be forgiven in time, yet in spite of all that you're probably STILL better off as a broke 20 something with an English degree and a bankruptcy on your record, than someone who has no undergraduate or vocational degree.
In a lot of ways what we see with downsizing is exactly the same thing. When your corporation is struggling, if you downsize and cut wages even tho the corporation dies a slow death it doesn't matter because the investors are a legally separate entity. In fact if your heavily downsized company happens to go bankrupt, as a shareholder you get to be potentially one of the people that gets a payout from the proceedings. Unafraid of bankruptcy, you can go for unsustainable growth in the short term and a quick sale. The only people who lose are you employees... and your customers... and your creditors... and whoever buys the company from you... and anyone lives in the area your company is based in... really everyone except the current investors. Meanwhile this encourages the consolidation of businesses since a mid or top of the pack corporation that dies is going to have its assets absorbed into larger corporations instead of smaller ones, pushing out of the market small businesses that could have had less toxic business practices and a more horizontal structure.
Of course Obama tried to relieve some of the pressure on the poor and young with public student loans and healthcare reform. So at least if the economy is going to go light on corporations it would go a little lighter on the little guy too. Now Republicans have rolled back what little student loan reform they didn't block, what they're doing to the education system is going to kill the prospects of anyone under say 14 years of age*, and they're trying to carve up our healthcare too. This shit is why I won't need to read a ballot for the rest of my life. I'm still going to out of principle, but like what would it take for a Democrat to be less in line with my beliefs than a Republican at this point?
*a little money is leaving universities and that's going to suck but a LOT of money is leaving K-12 public schools. What happens when public schools suck? Incoming students into universities don't have the base of knowledge to learn the advanced stuff, that causes dropout rates to increase, universities to make less money, and the people who do graduate will be less educated because more time will be spent on basics. This devalues college degrees and increases student loan debt while reducing the access to all levels of education for low income families. Fuck you Betsy Devos.