This is an important and timely discussion.
I wonder what is worse: having to pay the extra 15% (self-employment tax for declaring "pro gambler") or not being able to contribute to certain retirement savings with gambling winnings (for example, IRAs).
I suppose it's difficult to generalize but I'd like to see the numbers crunched on a few examples. I'm going to use tax software and create a few test cases to get a better feel for how bad it is.
But before crunching the numbers I thinks it's obvious that certain types of gamblers are getting screwed worse than others (well, we're -all- getting screwed -- except those living in gambling friendly countries, darn you!)
Let's take an extreme example, a gambler who wins enough in the year to put him in the highest tax bracket: are you telling me he is required to pay an -additional- 15% for self-employment SS tax? Good God, that puts him at about 50% taxes for everything over about $326,450. Further, even before he hits the 50% mark, he's paying about 43% on most of the rest (numbers off the top of my head)!
And that's only federal income tax, now we have to consider state taxes (unless you live in one of the handful of states with no state income tax, such as Nevada, Alaska, Florida, and a few others). State income taxes vary depending on state anywhere from 0% to about 9%, depending on income. Some states have flat-rates (Pennsylvania, for example, has a flat rate of 3.07% AGI) while others will mug you for more.
Oh, it's not over yet because now you have Local Taxes which, again, vary from location to location. They vary from very little or nothing to signifincat, that is, over 1% AGI.
If you factor in the taxes it is obvious the 'rule of thumb' about having to hit about 53% to break even realistic. Gambling income doesn't happen in a vaccuum and pretending you only need to win about 53% of your bets to break even doesn't make sense if you then get jacked by Uncle Sam for another 10% or 15% or more. Without doing the math, I'd have to estimate many sports bettors would have to hit 55% just to break even once the taxes are considered.
Again, it's difficult to make generalizations because the US tax laws are complicated. If I feel like it I will post the results of the example I run in the tax software to get something more solid.
The example I gave above is for a bettor who wins -huge-, but don't think that it's much different for a "low-roller". It may be -worse- for the little guy because he loses out on the much needed tax breaks mentioned in this thread. That is, not only is he bumped into the higher income bracket possibly, but he also loses the tax credits. As concluded earlier, he is in effect -paying- to break even. Not only that but if he's filing jointly with his wife it fucks her up too. It would have the same effect as if she were making a few dollars less an hour or making a signigicantly less salary per week! Even if her husband breaks even, she still loses out on the tax breaks and is possibly bumped into the next higher tax bracket. See the original poster's post for more details.
Well, wouldn't it be nice to just get away from it all? Run away to another country (preferably beather weather tax-haven country such as the Caymen Islands or similar). Well, that's a nice fantasy but there's a nasty little things that gets in the way and it's called Reality. US citizens must pay federal income tax no matter where they live on the planet (unlike in many European countries where you only have to pay taxes due to the place you live). You could be sitting in an igloo in Antartica and end up checking your mail to find out you're getting audited for your income from the previous year.
What if you want to become an ex-patriate and change citizenship? Well, the IRS has thought of that contingency too. If you have something like a net worth of $500,000 you're considered to be leaving to avoid taxes and it's going to be difficult. Further, even if they let you out, since you're declared to be leaving for this reason, you are still required to pay income tax for the next 10 years.
I'm starting to talk too long but to wrap it up: if you are a "high roller" it seems you are going to get hit with heavy taxes (up to about 50% winnings) and if you're a "low roller" you're going to get hit lose out on a lot of much needed tax breaks (mentioned in the OP's post) -and- pay significantly higher taxes. And lastly, there's nowhere to legally hide, no way out and no exit.