Latest NPS returns: NPS yields are tied to the market. The fund will be established based on the returns generated by stocks, corporate bonds, government securities, and alternative investment funds. NPS subscribers have the choice to open two accounts. A Tier I account is necessary to join NPS. What are the differences between Tier I and Tier II accounts? NPS yields are tied to the market. The fund will be established based on the returns generated by stocks, corporate bonds, government securities, and alternative investment funds.