Tax reform hasn't put dent in charitable giving. Yet.

Despite tax reforms that changed an important incentive for giving to charities last year, Americans are still giving away record amounts — just from funds they had put aside for donations in previous years.

Fidelity Charitable said last week that it has already surpassed its granting record from 2018, with $5.25 billion given to 125,000 different nonprofits so far in 2019. And that's with the traditional "giving season," that starts around Thanksgiving and runs to the new year, still six weeks away.

If the rest of this year matches last year, which included a slow December because of stock market volatility, Fidelity Charitable could tally up another $1 billion in giving before the end of 2019, said Pam Norley, president of Fidelity Charitable.

Still, this massive giving belies deep behavioral and demographic changes going on in the philanthropic world that have nonprofit organizations worried nonetheless.

There is still a tax deduction for charitable giving on the U.S. tax return, but many millions fewer people now itemize their deductions because the tax reform doubled the standard deduction. So, that incentive to give at the end of the year for the tax deduction is gone for most.

The long-term effect of this change will be greatest on community organizations that count on small, local donations.

"I know a lot of small organizations are nervous. It's hard to know what kind of programs to offer," said Eileen Heisman, president of the National Philanthropic Trust.

These accounts are particularly efficient for those who want to donate appreciated stock or other noncash assets, taking a tax deduction upfront and doling out the funds later. Organizations like Fidelity Charitable and Schwab Charitable administer these accounts and manage the granting process.

Granting may be higher in 2019 because the stock market, while volatile, is up over last year, said Fidelity's Norley.

Also, some people may have made a larger-than-usual donation in 2018 or 2019 in order to push them over the standard deduction limit, and will skip a year or two later on — a strategy known as bunching.

Most people are still figuring out how tax law changes are impacting their finances, so it could take up to three years before this factor settles down, Heisman said.