The company estimated the current market is worth between £1.2 billion and £1.5 billion a year with providers and advisers focusing on pension pots worth more than £50,000.
Directors at the firm said the Budget changes highlighted the continuing need for certainty on capital and income.
They forecast increased innovation and predicted more providers will be attracted to the market due to the end of the need to buy an annuity and retirement savers being allowed to access defined contribution funds whenever they like from April 2015 onwards.
Its analysis found around 33% of single life annuities and 45% of joint life annuities bought for premium sizes of more than £30,000 could benefit from unit-linked guarantee solutions – which may be suitable for the 21,000-plus new drawdown customers a year.
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Association of British Insurers' data showed annuity sales were already in decline before the Budget – having already fallen 16% in 2013 to 353,000 individual sales worth around £11.9 billion.
MetLife's research among advisers showed 62% believed products offering guarantees on capital and income have become more attractive following the Budget reforms – backed up by research which found retirement savers were concerned about the risks of outliving their pension savings.
Dominic Grinstead, managing director at MetLife UK, said: "Sales of guaranteed products which offer flexibility and certainty will take a much bigger share of the retirement income market in the future as innovation and competition increases.
"The current annuity market will change massively but the good things about annuities including guaranteed income for life and no risk of running out of money should be retained which is where unit-linked guarantees can play a major role.
"Clearly unit-linked guarantees are not suitable for all, but they enable advisers and clients to guarantee income and capital now and retain flexibility and freedom in the future as their circumstances change."