National Employment Savings Trust's assets increased more than 300% to £420 million ($622 million) in the year ended March 31.
In its latest annual report, the London-based national defined contribution plan said opt-out rates were an average 8%, and that 99% of participants are invested in its default option target-date funds.
The report said investment executives added ethically screened corporate bonds and single-year gilt funds to the underlying set of strategies during the year.
NEST is built around three phases: foundation, for younger participants; growth; and consolidation, for those approaching retirement.
The report published typical returns for each phase of NEST. A typical NEST target-date fund in the foundation phase returned 13.12% for the year ended March 31, vs. a benchmark return of -0.08% in the same period. The benchmark is the consumer price index. Over the three years ended March 31, the fund gained an annualized 9.8%, vs. 1.45% for the benchmark.
A typical fund in the growth phase, benchmarked against CPI plus 3%, gained 17.47% in the year to March 31, vs. 2.93% for the benchmark. Over three years, it gained 11.68% on an annualized basis, vs. 4.49%.
A typical NEST target-date fund in its final year of the consolidation phase returned 0.51% for the year, and 0.96% annualized for three years. The benchmark, the seven-day sterling London interbank bid rate, returned 0.35% for one year and 0.37% over three years on an annualized basis.
The report said NEST continues to hold “significant” positions in real estate, corporate bonds and equities. Asset allocation varies according to the phase. “We're gradually building up our portfolios' exposure to emerging markets with an eye on valuation and bearing in mind shorter term uncertainty,” the report said.