The iShares Core Cash ETF (ASX: BILL) offers Australians a simple, ultra-low-cost way to earn money-market returns on cash through a single ASX trade. By tracking an index of Australian bank bills, it provides a stable, income-focused holding that has become genuinely competitive with riskier Assets in an era of higher interest rates.

In September 2026, with the Reserve Bank holding its cash rate at 4.35% and Inflation still above target, the return available on cash and cash-like instruments is meaningful for the first time in years. This article explains how BILL works, why it is in focus, and the catalysts and risks that could shape it from here.

What is the BILL ETF?

BILL is a passive, cash-focused ETF issued by BlackRock under its iShares brand. It aims to provide the performance, before fees and expenses, of the S&P/ASX Bank Bill Index — a benchmark of short-term Australian bank bills. The fund charges an ultra-low management fee of 0.07% per annum, pays income monthly, and has been listed since 2017. It is designed to deliver stable, money-market returns with a high degree of Capital stability.

The defining feature is its focus on very short-term, high-quality instruments. By holding bank bills and cash-like securities with short maturities, BILL has essentially no duration risk, so its capital value is very stable and its return moves with short-term interest rates. It sits alongside other cash and enhanced-cash ETFs on the ASX, distinguished by its index-based approach and very low fee. Because it tracks bank bills, its return is closely tied to the prevailing short-term rate set by the RBA.

What is driving interest now?

The central driver is the level of short-term interest rates. With the RBA holding at 4.35% and the market weighing whether rates have peaked, the Yield available on cash and bank bills is at its most attractive in years. That has made cash ETFs like BILL a credible alternative to leaving money in a low-rate transaction account, and a genuine competitor to riskier assets for the defensive portion of a portfolio.

A second driver is uncertainty. When Equity and bond markets are volatile, some investors value the capital stability and Liquidity that cash provides, using a fund like BILL to park money while earning a competitive return. Its ultra-low 0.07% fee means more of the bank-bill return flows through to investors. The key point is that BILL’s income moves with short-term rates: while the RBA holds at 4.35%, its yield stays elevated; if the RBA eventually cuts, the income would decline.

Portfolio and holdings

BILL’s portfolio consists of short-term Australian bank bills and cash-like securities, tracking the S&P/ASX Bank Bill Index. It does not hold shares or longer-dated bonds, so there are no equity holdings or meaningful duration exposures to analyse. The most important features are the short-term, high-quality nature of its holdings and the prevailing short-term interest rate.

Because it holds very short-term instruments, BILL’s unit price is designed to be very stable, with returns delivered almost entirely through the monthly income distribution. Investors should note that, like other cash ETFs, money held in BILL is not covered by the Australian Government’s Financial Claims Scheme guarantee that applies to eligible deposits held directly with a bank. Its returns are closely tied to the RBA’s cash rate and short-term bank-bill rates.

Catalysts to watch

Several factors could influence BILL in the coming months: the RBA’s 29 September rate decision and the future path of the cash rate; short-term bank-bill rates; the relative appeal of cash versus shares and bonds during any market volatility; and broader trends in Australian inflation that shape monetary policy.

Risks

BILL is among the lowest-risk ETFs on the ASX, but it is not risk-free. Interest-rate risk works in reverse to bonds: if short-term rates fall, BILL’s income declines. Its returns are unlikely to keep pace with inflation over the long term, so it carries the risk of eroding real purchasing power if used as a long-term holding. Cash-like holdings in the ETF are not covered by the Government’s deposit guarantee. There is minimal Credit risk given the high-quality bank bills. It is a capital-preservation tool, not a growth investment.

Outlook

BILL offers Australians an ultra-low-cost, stable way to earn money-market returns on cash, combining capital stability, monthly income and easy ASX access. Its near-term appeal depends squarely on short-term interest rates: while the RBA holds at 4.35%, cash yields remain competitive. Investors may be watching the September RBA decision and the future rate path for direction. The outlook may depend on how long rates stay elevated, since BILL’s income moves directly with short-term rates.