Ironically, the BSTZ term expiration in 2031 might dissuade some retirees from considering it as a portfolio addition. While certain Exchange Traded Funds, Mutual Funds, and Closed End Funds all vie for market share, BlackRock is the asset management 800 lb. This high reliable consistency and its BlackRock name imprimatur of safety score big points with retirees. This is not unlike the scenario of callable municipal bonds, which run a risk of early redemption by the issuer. In retrospect, BSTZ can be a solid choice for retirees, albeit ones who clearly understand the pros and cons of investment in a technology fund.