The split verdict in the May CPI, a headline miss and a core beat, is the worst combination for the RBA's communication task. The bank cannot claim the inflation problem is resolving while trimmed mean is running 1.1 percentage points above the midpoint of its target band and 0.6 points above the band's ceiling, and accelerating. The fuel excise extension to end-July provides a mechanical buffer on the headline for one more month, but it actively complicates the underlying signal and the RBA has been explicit that secondary pass-through from energy costs into broader prices remains a concern. Markets moving to 36% for an August hike and 67% for December reflect a board that is not yet compelled to move but is far from done. The labour force data due later this week is now the fulcrum: a soft unemployment print could push August hike odds back toward 50%, while any deterioration in employment conditions would take pressure off a board that has already delivered three hikes this year. The AUD's flat response and the two-basis-point slip in three-year yields suggest the market read this as a modest hawkish tilt that changes nothing decisively.---Australia's May headline CPI slowed to 4.0%, below the 4.3% forecast, but trimmed mean core inflation rose to 3.6%, above estimates, keeping RBA August hike odds at around 36%. Summary:Australia's May headline CPI fell 0.7% month-on-month and slowed to 4.0% year-on-year, below the 4.3% consensus and the prior 4.2%, driven by falls in petrol, clothing and holiday travel, according to the Australian Bureau of StatisticsTrimmed mean core CPI rose 0.4% month-on-month and 3.6% year-on-year, above the 0.3% monthly forecast and accelerating from 3.4% in April, sitting 1.1 percentage points above the RBA's 2.5% target midpoint and 0.6 points above the top of the bandThe weighted median, the second core measure, rose 0.4% month-on-month and 3.6% year-on-year, up from 3.5% and 0.2% respectively in April, corroborating the trimmed mean accelerationFuel prices fell 11.9% month-on-month in May following a 7% decline in April, reflecting lower global oil prices and the government's fuel excise cut, which has since been extended at 50% through to end-JulyThe RBA has raised the cash rate three times in 2026 to 4.35%, fully reversing 2025 easing, and had forecast headline CPI peaking at 4.8% in Q2 and trimmed mean reaching 3.8%, both now tracking below those levelsMarkets are pricing approximately 36% odds of an RBA hike in August and around 67% for December, with this week's labour force data, particularly the unemployment rate, seen as the next key input for the policy outlookAustralia's May consumer price index delivered a split verdict on Wednesday that leaves the Reserve Bank of Australia's policy calculus essentially unchanged: headline inflation slowed more than expected, but core inflation accelerated, keeping the prospect of a fourth rate hike this year firmly on the table.The Australian Bureau of Statistics reported that headline CPI fell 0.7% in May from the prior month, pushing the annual pace down to 4.0% from 4.2% in April and undershooting the market consensus of 4.3%. The monthly decline was driven by falls in petrol, clothing and holiday travel costs. Fuel prices dropped 11.9% in the month, following a 7% decline in April, reflecting both lower global oil prices in the wake of the US-Iran ceasefire and the government's fuel excise reduction. That excise cut has since been extended, at 50% of its original size, through to the end of July, providing a further mechanical drag on the headline reading for at least one more month.The relief on the headline, however, was undermined by the core measures. The trimmed mean rose 0.4% in May, above the 0.3% forecast, pushing the annual pace up to 3.6% from 3.4% in April. The weighted median, the second core measure the RBA monitors closely, also rose 0.4% on the month and 3.6% on the year, up from 3.5% and 0.2% respectively. Both readings sit 1.1 percentage points above the midpoint of the RBA's 2% to 3% target band and 0.6 points above the band's ceiling, and both are moving in the wrong direction.The RBA entered 2026 with its own forecasts calling for headline inflation to peak at 4.8% in the second quarter and trimmed mean to reach 3.8%. Both are tracking below those projections, partly because the Iran ceasefire has driven oil prices sharply lower in a development the bank would not have anticipated when those forecasts were published in May. The RBA has nonetheless maintained that it remains concerned about secondary effects from the energy shock feeding through into broader prices, a caution that Wednesday's core acceleration does nothing to dispel.The bank has raised rates three times this year to 4.35%, fully reversing the easing implemented in 2025, and the May data does not provide sufficient cover to rule out a fourth move. Markets moved to price approximately 36% odds of an August hike following the release, with December sitting at around 67%, reflecting a board seen as on hold for now but far from finished. The Australian dollar was flat at around $0.6917, and three-year government bond yields slipped two basis points to 4.399%, consistent with a market that read the report as a modest hawkish tilt rather than a decisive signal in either direction.The next pivot point is this week's labour force data, with the unemployment rate in particular seen as the variable most likely to shift the August calculus. A tighter-than-expected labour market would reinforce the case for the RBA to move again; any sign of softening employment conditions would give the board reason to wait and watch the core inflation trajectory for another month before acting.---Next meeting is 7 or so weeks away: This article was written by Eamonn Sheridan at investinglive.com.