Individual retirement account assets reached an estimated $5.3 trillion in the first quarter of 2012, a nearly 9 percent rise over the $4.8 trillion in estimated assets for 2011, according to a new report.

Cerulli Associates, Boston, released this finding in the November edition of “Evolution of the Retirement Investor 2012: Understanding 401(k) Participant Dynamics and Trends in Rollover and Retirement Income,” a Cerulli Special Quantitative Update. The report includes an analysis of defined contribution plan participants, individual retirement account (IRA) assets and the rollover decision, and the retirement income landscape.

Rollover contributions totaled $307 billion in 2011. Nearly two-thirds of the assets (65.4 percent or $207 billion) were rolled over through an advisor, the average balance of a rollover totaling $115,000. Of the $201 billion, 83 percent ($167 billion) was handled by an existing advisor. The balance ($34 billion or 17 percent) went through a new advisor, the research shows.