Most people encounter the Charitable Lead Trust as an estate planning tool before they encounter it as a charitable one. That is not wrong. The CLT is primarily a mechanism for transferring assets to the next generation at a reduced gift or estate tax cost. The charitable component is real and meaningful, but it is also part of what makes the economics work.
Here is how it works. You fund the trust with assets. The trust pays an income stream to a charity or charities for a defined term, typically 10 to 20 years. At the end of that term, the remaining assets, which ideally have grown beyond the original contribution, pass to your heirs. Because the charity's income interest reduces the taxable value of the gift to your heirs, the transfer happens at a fraction of what it would otherwise cost in gift or estate taxes.
The CLT is most powerful in a low interest rate environment, when the IRS discount rate used to calculate the charitable deduction is favorable. It is also most appropriate for donors who genuinely want to support a cause over a meaningful time period, not simply as a tax mechanism.