• First quarter GAAP earnings per share were $0.87 in 2026, compared to $0.83 in 2025
• First quarter ongoing earnings per share were $0.82 in 2026, compared to $0.83 in 2025
• Reaffirming 2026 ongoing earnings guidance range of $3.36 - $3.46 per share
• Signed an approximately 370 MW electric service agreement in Iowa, total contracted data center demand is now approximately 3.4 GW

“We are off to a strong start in 2026, delivering approximately 25 percent of our ongoing earnings guidance midpoint, and reaffirming our full-year ongoing EPS outlook,” according to Lisa Barton, Alliant Energy President and CEO. “Our results reflect disciplined execution and continued momentum in data center growth, including the signing of a new electric service agreement in Iowa for approximately 370 megawatts of contracted demand. With five executed agreements, we are translating customer demand into well-structured, long-term growth that benefits investors, existing customers and communities.”