Our tax code includes a number of “heads billionaires win, tales other taxpayers lose” provisions. Lawmakers are currently debating new tax rules that could fix these loopholes, but so far the House Ways and Means Committee will leave most of them in place.

How does a billionaire pass on wealth to avoid or reduce estate taxes?  Their “wealth defense industry” employees — the tax attorneys and estate planners who are paid millions to sequester trillions — have an alphabet soup of tricks up their sleeve along with trusts.  Welcome to the world of GRATS, IDGTs, and valuation discounts.

Want to become the best investor ever? Imagine if you only had to keep your high-performing investments and could sell back the money-losers at no cost. Imagine that on those high-return investments the person selling to you would continue to pay all the income tax. And, for each investment, imagine you could borrow 100 percent of the purchase price from your seller, at a low interest rate.

Now, what if you were super wealthy and you wanted to sell an investment, but you only got paid if the investment increased in value after the sale? Otherwise, you’d have to take it back, no questions asked. And, either way, the tax on the income from the investment would be on you.

That, my friends, is how America’s billionaires avoid estate and gift tax entirely. They sell assets to trusts that benefit their children under the rules described above. And they do it repeatedly. Eventually, those trusts own virtually all the wealth, without any taxable gifts taking place. Just a series of outstanding investments. And no bad ones. Those asset sales, by the way, are not subject to income tax.

Tax avoidance planners call this strategy a zeroed-out GRAT, which stands for grantor retained annuity trust. The mechanics of a zeroed-out GRAT are super-complicated, but look past the complexity and what you have is an asset sale that is reversed if the asset fails to perform. Oh, and that little wrinkle about the seller continuing to pay the income tax.

Is it really that easy? No, it’s even easier.

Consider what a breeze investing would be if your seller gave you a 30 percent discount on each investment. That tax avoidance strategy is known as a valuation discount. A wealthy parent takes her investment assets and contributes them to, say, a limited liability company in exchange for all the LLC interests. You’d think all those LLC interests would be worth the same thing as the investment assets, but tax avoidance planners would contend they’re worth about 30 percent less. And they’ve convinced judges they’re right.

So, when super-rich parents sell assets to one of those trusts for their children, the kids’ trust gets a nice discount. And the parents keep paying the income tax.

These trusts where the trust creator keeps paying the tax, by the way, are known in the estate tax avoidance world as intentionally defective grantor trusts, IDGTs for short.

Often, ultrarich people have assets they’re not terribly worried could lose value. They sell those to IDGTs too, but in a different way. First, they make a smallish (for them, that is) cash gift of about $10 million or so to the trust. Then, they sell assets having a value about ten times the amount of the gift to the trust, in exchange for the cash and a promissory note that bears interest at a super low rate. If the assets increase in value, the trust can buy more assets from the ultrarich person who created the trust, paying 100 percent of the purchase price with a promissory note.

Why, you might wonder, would an ultrarich person use this strategy rather than a zeroed-out GRAT? After all, the zeroed-out GRAT doesn’t require the gift of any seed money, which can be wasted if the IDGT’s assets decline in value. Here’s why: If this other strategy, which avoidance planners call sale to an IDGT, works out, and it usually does, the trust winds up being what’s known as a dynasty trust.

Once wealth finds its way into a dynasty trust, it escapes all wealth transfer tax (that is, estate and gift tax and a third tax known as the generation-skipping transfer tax, or GST) forever, even in perpetuity. How large can one of these dynasty trusts get? The Northern Trust Company provides an example: A dynasty trust starting at $11.7 million and growing at 5 percent per year would hold $454 million after 75 years. Consider how much a dynasty trust would hold if it started out at $100 million. Or $1 billion. Or if the trust lasted 175 years. Or if it grew at a yearly rate greater than 5 percent.

There is some good news on this front. Congress is finally considering legislation that will put a major crimp in billionaire tax avoidance planning. Legislation being considered by the House Ways and Means Committee would partially address IDGTs and valuations discounts. But it doesn’t go nearly far enough. And it fails to rule out the worst abuse, zeroed-out GRATS. Dynasty trusts would still be around as well. There are fixes for GRATs and dynasty trusts, as well as improvement to the proposals to address IDGTs and valuation discounts. Those need to be incorporated into the legislation.

Four years ago, Trump economic adviser Gary Cohn derisively noted that “only morons pay estate tax.” Derision aside, Cohn was correct that the estate tax essentially is a voluntary tax. We now have a chance to change that. Let’s make it happen.