Investors who underdiversify their portfolios often face higher risk during market downturns.

By underdiversifying their portfolios, many novice investors expose themselves to unnecessary risk.

When she underdiversifies her portfolio, she increases the risk of large losses during market downturns.

Having underdiversified his portfolio, he regretted putting all his savings into one startup.

The startup's investment portfolio remained underdiversified, leaving it vulnerable to sector-specific downturns.