The four largest life insurers in Japan have reported that their total unrealized losses on domestic bond holdings increased by 7% in the three months ending June 30, highlighting the risks a spike in yields poses to the country's insurance sector. According to financial data for the April-to-June quarter, the combined unrealized losses on bond holdings for Japan Life Insurance Co., Dai-ichi Life Holdings Inc., Sumitomo Life Insurance Co., and Meiji Yasuda Life Insurance Co. expanded to 15.13 trillion yen (approximately $96 billion).

However, with the exception of Japan Life Insurance Co., the other three insurers all saw an increase in unrealized losses on their bond holdings. The decline in bond prices also triggered impairment accounting treatment for some positions, which occurs when a bond's market value falls more than 50% below its purchase cost, requiring an asset impairment loss to be recognized. Japan Life Insurance Co. recorded around 44 billion yen in impairment losses, while Meiji Yasuda Life Insurance Co. recognized 25.3 billion yen in such losses.

Japanese life insurers typically hold Japanese government bonds and other debt securities to maturity in order to meet insurance liability needs. However, if customers surrender policies en masse, these companies may need to sell bonds to pay out claims, potentially straining their profitability and investment portfolios. In a regulatory report released on August 6, the Japanese Financial Services Agency stated that the widening unrealized bond losses are affecting insurers' financial accounting processes and liquidity conditions, and regulators are closely monitoring the investment activities of insurance companies.

Amid market concerns that the government of Prime Minister Shigeru Ishiba may increase fiscal spending to support the economy, the yield on Japan's 30-year government bond surpassed 4% in May, hitting a historic high. These ultra-long-term bonds are a primary investment target for life insurers. The sell-off in Japanese government bonds during the second quarter reflects two mutually reinforcing pressure lines. The first is global inflation transmission—war-driven energy price increases are pushing up borrowing costs for governments around the world, and Japan cannot escape this trend. The second is a domestic fiscal concern. The policies of Prime Minister Ishiba have sparked market worries about Japan's fiscal discipline.

Although the yield on Japan's 30-year government bond has recently declined, the three pressures of the Bank of Japan's gradual interest rate hikes, rising global term premiums, and the government's massive bond issuance plan are expected to continue weighing on Japanese bond prices. As the Bank of Japan gradually reduces its bond purchases, investors are increasingly concerned about one question: Who will absorb the government's growing debt? The prospect of stronger domestic demand has therefore become particularly important. A previous calculation by Societe Generale showed that Japan's Government Pension Investment Fund (GPIF) could purchase an additional 12.3 trillion yen (about $76 billion) in Japanese government bonds without changing its benchmark asset allocation framework. This estimate by SocGen is based on a simple assumption: GPIF gradually increases its domestic bond holdings from 26.9% in March to the upper limit of 31% allowed under the current system. In the medium term, even if it only gradually increases its domestic bond allocation within the existing permissible range, GPIF could still release between 76 billion and $90 billion in potential buying power. However, SocGen also warns that the fundamental problem with Japanese government bonds lies in supply-demand imbalance—"stable auction supply and accelerated quantitative tightening increase bond supply, while domestic investor demand weakens and global term premiums rise."