In such instances, investors may be forgiven for wondering if diversification really works.
Interestingly, various studies have observed that the correlation between equity markets tends to be asymmetric2. This means that correlations tend to increase in down markets, especially during sharp downturns, and fall when markets are rising.
This is bad news, as investors desire diversification most when markets are falling.
Why do market correlations rise, when markets fall? It is believed that this occurs because risk aversion is highly contagious, and investors tend to react more strongly to bad news than to good.
On a more comforting note, studies also suggest that the low or negative correlations between equity and bond prices are more persistent3. Equity and bond prices tend to move in opposite directions when market uncertainty is high4. Apart from changes in the macro environment and valuations, investor risk sentiment has an important impact on the relationship between equity and bond prices. Very often during periods of market turbulence, the equity risk premium demanded by investors rises, relative to the term premium for bonds. This “flight to safety” in turn causes the prices between bonds and equities to diverge.
The negative correlations between stocks and bonds are also more enduring when inflation expectations are low. This is because rising inflation expectations drive up discount rates which hurt bonds. On the other hand, at high levels of inflation, the changes in the discount rates dominate the changes in cash flow expectations for equities, in turn causing bond and equity prices to move in the same direction. With inflation expected to remain subdued in the foreseeable future while markets stay choppy, bonds can still offer some diversification benefits for investors. See Fig. 2.