Modified endowments

Endowment Life Insurance Policy
in response to single-premium life (endowments) being used as tax shelters. They are contracts with fewer than 7-level annual premiums, and are subject to more stringent tax regulations (tax code 7702, 7702A). They are also subject to IRA-like annuity rules (such as penalties for pre-death proceeds before age 59½). If a life insurance policy is changed and then fits the seven-pay rules, it may then be redefined as a modified endowment.

Try also this links of best pages on endowments:
Traded Endowment Policy o
Wikipedia Endowment Policy o Endowment Policy Blogs o o Endowment Policies Guide o