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FORM 6-K

U.S. SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

Report of Foreign Private Issuer

Pursuant to Rule 13a-16 or 15d-16 of

the Securities Exchange Act of 1934

Commission File Number: 333-163336

For the month of March 2011.

NKSJ Holdings, Inc.

(Translation of registrant’s name into English)

26-1, Nishi-Shinjuku 1-chome

Shinjuku-ku, Tokyo 160-8338

Japan

(Address of principal executive offices)

Indicate by check mark whether the registrant files or will file annual reports under cover Form 20-F or Form 40-F.

Form 20-F      X                Form 40-F              

Indicate by check mark if the registrant is submitting the Form 6-K in paper as permitted by Regulation S-T Rule 101(b)(1):             

Indicate by check mark if the registrant is submitting the Form 6-K in paper as permitted by Regulation S-T Rule 101(b)(7):             

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Information furnished on this form:

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Impact of the Tohoku Pacific Earthquake on the NKSJ Group

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SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.

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[English Translation]

March 16, 2011

Impact of the Tohoku Pacific Earthquake on the NKSJ Group

As those affected by the Tohoku Pacific Earthquake of March 11, 2011, work to recover, the NKSJ Group expresses its heartfelt sympathy and solidarity. Following is a summary of how the NKSJ Group has been affected so far.

1. Impact of the Disaster on Operations

Some buildings and equipment of NKSJ Group companies in disaster affected areas have sustained damage or been otherwise affected. Operations have been suspended at some branches and offices in affected areas of NKSJ Group insurance companies Sompo Japan Insurance Inc., Nipponkoa Insurance Co., Ltd., Saison Automobile & Fire Insurance Co., Ltd., and Sompo Japan Himawari Life Insurance Co., Ltd.

2. Impact on Financial Results

The NKSJ Group’s insurance companies have set up response headquarters and implemented other response measures, and are currently handling inquiries and accident reports associated with damage resulting from the earthquake.

The Group is currently investigating what impact, if any, the earthquake will have on its financial results and will immediately release a revised earnings forecast for the current fiscal year if necessary in light of the investigation’s outcome.

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Note Regarding Forward-looking Statements

This document includes “forward-looking statements” that reflect the information in relation to the NKSJ Holdings, Inc. (“NKSJ”). To the extent that statements in this document do not relate to historical or current facts, they constitute forward-looking statements. These forward-looking statements are based on the current assumptions and beliefs of NKSJ in light of the information currently available to NKSJ, and involve known and unknown risks, uncertainties and other factors. Such risks, uncertainties and other factors may cause the actual results, performance, achievements or financial position of NKSJ, as the case may be, to be materially different from any future results, performance, achievements or financial position expressed or implied by these forward-looking statements. NKSJ does not undertake or will not undertake any obligation to publicly update any forward-looking statements after the date of this document. Investors are advised to consult any further disclosures by NKSJ in their subsequent domestic filings in Japan and filings with, or submissions to, the U.S. Securities Exchange Commission pursuant to the U.S. Securities Exchange Act of 1934.

The risks, uncertainties and other factors referred to above include, but are not limited to, those below. The risks, uncertainties and other factors are also referred to in our domestic Quarterly Securities Reports.