Updates with details from paragraph 2 onwards

May 18 (Reuters) - Australia's Brambles BXB.AX trimmed its annual profit growth outlook on Monday due to U.S. subcontractor repair-capacity constraints, triggering a sharp sell-off that saw its shares notch their weakest intraday session in over two decades.

Shares of the Sydney‑based firm slides as much as 20% to A$17.68, its lowest level in nearly two years. The stock also marked its steepest intraday drop since late November 2002, landing among the ASX200's .AXJO worst performers as the benchmark slips 1.4%.

The logistics group now expects full-year 2026 underlying profit growth of just 3%-5% on a constant-foreign-exchange basis, sharply downgraded from its earlier 8%–11% outlook.

Brambles said short‑term repair bottlenecks that surfaced in April across the U.S. Central and Northeast, driven by factors such as labour shortages and the extra time needed to create pallets of higher standards. These are expected to dent full-year 2026 earnings by about $60 million.

The company is also contending with higher customer demand and plans to ramp up pallet relocations, expand additional repair capacity, and purchase new pallets, with around 2 million planned for the fourth quarter to ease the squeeze.

The company also said it remains confident that the challenges will be resolved by the end of the first half of 2027.