The fee for the UBS ETF Barclays TIPS Ucits fund has fallen from 0.20% to 0.15% after coming into effect on 1 April this year.
Fees for the currency hedged versions of the ETF have also been cut, to 0.20% from 0.25%.
The cuts were made possible due to the increasing size of the ETFs, UBS said, with total assets now more than $600m (£467.7m).
The asset manager confirmed it would be expanding its fixed income ETF range, and credited growing investor concerns over inflation for the ETF's success.
Clemens Reuter, global head of investment specialists passive & ETFs, said: “After an extended period of low interest rates there is growing evidence in markets of inflationary pressures starting to build, particularly in the US.
"With this innovative fixed income product, our clients are able to protect long-term purchasing power and gain access to an asset class that compounds the real rate of return."