Free Writing Prospectus

Filed Pursuant to Rule 433

Registration Statement No. 333-278797-03

NORTHERN STATES POWER COMPANY

(a Wisconsin corporation)

$400,000,000 5.65% FIRST MORTGAGE BONDS, SERIES DUE JUNE 15, 2054

Issuer:	Northern States Power Company (a Wisconsin corporation)
Issue Format:	SEC Registered
Expected Ratings*:	Aa3/A/A+ (Negative/Negative/Stable) (Moody’s/S&P/Fitch)
Security Type:	First Mortgage Bonds
Pricing Date:	May 13, 2024
Settlement Date:	May 16, 2024 (T+3)
Principal Amount:	$400,000,000
Maturity Date:	June 15, 2054
Interest Payment Dates:	Semi-annually on June 15 and December 15, commencing December 15, 2024
Reference Benchmark:	4.250% due February 15, 2054
Benchmark Price:	93-31
Benchmark Yield:	4.625%
Spread to Benchmark Treasury:	+105 bps
Yield to Maturity:	5.675%
Coupon:	5.65%
Price to Public:	99.634% of the principal amount
Net Proceeds to Issuer:	$395,036,000 (after deducting the underwriting discount but before transaction expenses)
Make-Whole Call:	Prior to December 15, 2053 (the par call date), T +20 bps (calculated to the par call date)
Par Call:	On or after December 15, 2053, at par
CUSIP/ISIN:	665789 BC6 / US665789BC69
Minimum Denominations:	$2,000 and integral multiples of $1,000 in excess thereof
Joint Book-Running Managers:	BMO Capital Markets Corp. KeyBanc Capital Markets Inc.

* Note: A securities rating is not a recommendation to buy, sell or hold securities and may be subject to revision or withdrawal at any time.

The issuer has filed a registration statement (including a prospectus) with the SEC for the offering to which this communication relates. Before you invest, you should read the prospectus in that registration statement and other documents the issuer has filed with the SEC for more complete information about the issuer and this offering. You may get these documents for free by visiting EDGAR on the SEC website at www.sec.gov. Alternatively, any underwriter or any dealer participating in the offering will arrange to send you the prospectus if you request it by calling BMO Capital Markets Corp., toll-free at 1-866-864-7760 or KeyBanc Capital Markets Inc., toll-free at 1-866-227-6479.