Confirming the old adage that people love ‘free stuff’, in the month since Fidelity unveiled the first no-fee index fund, the massive asset manager has seen its new funds flooded with $1 billion in AUM.

On August 1st, the closely-held Fidelity announced it would offer two new index funds to individual investors with a zero expense ratio. The funds, which will track indexes Fidelity created, will give investors exposure to the total U.S. stock market and an international benchmark. 

One month later, things have started well, as Bloomberg reports that the Fidelity Zero Total Market Index Fund attracted $753.5 million through Aug. 31, while the Fidelity Zero International Index Fund gathered $234.2 million, according to Fidelity’s website.

“A billion in a month is a great showing when you consider that the funds are available only to retail investors”, said Ben Johnson, head of global ETF research at Morningstar Inc.

Incidentally, since inception, the Total Market Index Fund has outperformed the S&P 500 in August…

While Fidelity, which manages $2.5 trillion, is best known for its actively-managed funds, in the past few years it has aggressively gone after rivals in the “passive” index arena, and now has about $400 billion in index mutual funds according to Bloomberg.

Russel Kinnel, director of manager research at Morningstar, said the zero-price funds might attract new business. “Fidelity has lots of ways to make money from customers once they are in the door”, he said. “This could work for them”.