The Danube at Ruse sank a metre under zero and Constanța's premium over Romania's river silos widened by 21.57 EUR/t on the year, while Hungary, barred from Ukrainian maize, imports from its neighbours.

Why these three series belong together

Three open series: the Danube level at Ruse (EAEMDR), the gap between Constanța FOB feed maize and the Muntenia departure-from-silo price, both Romanian notifications to DG AGRI, and Hungary's monthly maize imports (Eurostat Comext). Open daily Ruse levels cover 2024, 2025 and 25 October to 1 November 2026, with none for July to 24 October 2026; the record itself, −145 cm on 21 October and 72 cm under the 2003 low, is the figure of Bulgaria's deputy transport minister as reported by BTA.

What the river did

From 25 October to 1 November the Ruse gauge read between −134 cm [F1] and −120 cm [F2]. The lowest daily mean of 2025 was −59 cm [F4]; on 1 November 2025 the gauge read −15 cm [F5] (+187 cm [F8] in 2024). TTS, the largest Romanian river operator, reports navigation upstream of Cernavodă interrupted since July and three river terminals suspended; below Cernavodă its barges loaded at most 800 to 1,000 tonnes.

What the prices did

Constanța FOB rose from 191.70 EUR/t in week 27 [F12] to 244.49 in week 43 [F13], against 200.62 a year earlier [F14]. The Muntenia silo price moved from 194.94 [F37] to 203.65 [F36]; Oltenia's, furthest up the river, fell from 204.30 [F41] to 185.29 [F39]. The FOB-minus-Muntenia gap went from −3.24 in week 27 [F44] to 22.19 in week 39 [F56], 66.69 in week 40 [F45] and 40.84 in week 43 [F42], 21.57 EUR/t wider than the 19.27 of week 43 of 2025 [F43]; Romania notified no FOB price in most summer weeks.

The gap over the Bulgarian Ruse price went from 14.70 [F19] to 59.49 EUR/t [F20], against 8.88 a year earlier [F21]. That notification stood at 177.00 [F16] from week 2 to week 38 and has read 185.00 [F17] since, so it puts the Ruse gap 18.65 EUR/t above the Muntenia gap in week 43: the frozen price inflates the level, while the widening from week 27, 44.79 EUR/t over Ruse and 44.08 over Muntenia, shows in both.

What Hungary imported

Hungary imported 30,469 tonnes of maize in August 2026 [F25], 9,888 from Slovakia [F30] and 8,505 from Romania [F31]. Last winter brought 90,397 tonnes in November 2025 [F26] and 118,774 in December [F27]. Since May, Decree 91/2026 admits Ukrainian maize only in transit. The Great Plain farm gate stood at 235.86 EUR/t in week 43 [F23], against 185.26 a year earlier [F24].

The mechanism, and what else could explain it

Hypothesis · Below Cernavodă a barge carrying 1,000 tonnes instead of 1,700 needs at least 1.7 times the full-load freight per tonne, and above Cernavodă the barge is not there at all, so Muntenia and Oltenia maize goes by truck or rail or waits in silo. If the port price is set by its buyers and the silo keeps what is left after the trip, Oltenia should fall while Constanța rises, as it did [F39]; who keeps the gap is not yet measured.

Hypothesis · S&P Global Platts reports Turkish buyers switching from Ukrainian to Romanian, Serbian and Bulgarian corn, with farmers slow to sell at harvest: that demand pull could hold the gap open whatever the water does, and it rests on one publisher. The regional crop shortfall lifts every price, not the port's premium over Romania's own silos.

Who sits on this chain

TTS states the interruption and its force-majeure contracts in its half-year filing. Comvex's general director says the low river cuts the grain reaching its Constanța terminal; RWA Raiffeisen Agro Romania's head of trade says the corridor feeding the port has no slack; Forumul APPR, the farmers' federation, reports fewer barge rotations and dearer freight; Danube Logistics' Giurgiulești port loads ships in two stages. Hungrana warns that processors could stop if Hungarian maize runs out by February 2027.

Hypothesis · Deduced positions: Cargill, co-owner of the Canopus terminal, and Umex earn less on lighter barge arrivals; Pannonia Bio, at Dunaföldvár, buys at import parity by rail and road; Touax gains lease demand; Ukrainian Danube Shipping competes for the same draught.

A conditional sensitivity, not a forecast

Scenario · Hungarian processors count 1 to 1.2 million tonnes as obtainable from EU neighbours and Serbia. Assume the low end, 1.0 million: over twelve months, 83,333 tonnes a month, 2.7 times August's 30,469 [F25]. Last winter already ran above that [F26] [F27], so the volume would arrive whatever the Danube does; the river would show, if at all, in the partner mix.

What would change this reading

Hypothesis · If on 30 November Ruse is back at or above −60 cm, the FOB-minus-Muntenia gap should fall to 35 EUR/t or less in December, toward its late-2025 prints of 37.35 [F46] and 11.00 [F47]; if the river stays below −60 cm, it should hold at 35 or more. A gap above 35 with the water back would favour Turkish demand over the river; a gap under 25 while Ruse is still below −100 cm would break the river reading. Hungarian imports under 60,000 tonnes in November or December would break the deficit arithmetic; a lifting of Decree 91/2026 would show how much of the Great Plain premium is regulation.