BT Group Plc said it plans to cut its labor force, including employees and contractors, by as much as 42% by the end of the decade after the UK’s biggest network operator completes its nationwide fiber-optic rollout.

The company’s workforce will drop to 75,000 to 90,000 people by the fiscal year ending in March 2030 from about 130,000 currently, the company said in its full-year earnings statement on Thursday.

Chief Executive Officer Philip Jansen is slashing costs at BT, fighting an industrywide slump as telecom carriers spend heavily on their networks. He’s pledged to cut expenses by £3 billion ($3.7 billion) a year by 2025 from its base in 2020 and has been weighing more dramatic job cuts since at least 2019.

But he’ll have to wait for the company to finish its fiber-optic rollout, a project to replace much of BT’s slower, copper-based network with higher-speed connections to reach 25 million homes by the end of 2026. Meanwhile, the company said its free cash flow is likely to decline to as low as £1 billion this fiscal year and BT was vague about its earnings for the period, saying they would grow without giving a specific number.

The shares fell 8.7% to 135.20 pence at 8:24 a.m. in London trading after earlier falling as much as 10%, the biggest intraday decline in six months. The company’s stock had gained 32% so far this year through Wednesday.

The company had 97,148 full-time employees as of the end of March with about a third of those working for its Openreach network division.

BT also posted adjusted fourth quarter earnings of £2.05 billion before interest, tax, depreciation and amortization. That compared to the £1.99 billion average forecast from analysts in a Bloomberg survey. The company also hit a long-term target for full-year earnings of £7.9 billion that Jansen had originally set out in 2020.

What Bloomberg Intelligence Says:

BT’s consensus-matching fiscal 2023 results and plan to accelerate full-fiber investment from FY24 underscore the carrier’s solid execution against a strategy that aims to deliver sustainable sales and profit growth. An ambitious, but achievable, plan to cut the labor force (including third-party workers) by 30-42% over the midterm adds further clarity to the reiterated goal to add £1.5 billion (115%) to annual cash flow by the end of the decade.

— Matthew Bloxham, BI media and telecoms analyst

--With assistance from Henry Ren.

(Updates with additional context on the earnings throughout. A previous version of the story corrected the day of the week)