The company has today reported the large fall as part of its first quarter results.
In a statement, the Scottish-based business said: "Changes to annuity regulations in the UK resulted in a reduction in our UK annuity sales of around 50% following the Budget announcement.
"While it will be some time before long-term trends become clear, the negative profit impact of the changes will reflect the relatively small size of our annuity business."
The exact figures were not disclosed in the report.

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The firm's assets under administration were up 1.5% to £247.8bn driven by net inflows of £2.4bn and its fee revenue was up 12% to £374m.
In the UK business fee retail and corporate net flows increased by 75% to £0.7bn with the platform continuing to attract assets.
Standard Life also reported a 16% increase in regular premiums in the corporate pension business and adviser firms using its platform went up 8% to 1,256 with wrap customers up 26% to 142,000 over the last twelve months.
Total platform AUA increased by 25% to £20.3bn with wrap platform assets £17.5bn, up 28% on Q1 2013.
Paul Matthews, chief executive, UK and Europe at Standard Life, said there had been "unprecedented changes" to the industry in this period.
He said: "The changes made to allow customers to access their money instead of having to purchase an annuity will provide customers with more flexibility, which is a good outcome.
"While we will see less annuity business going forward our market-leading drawdown proposition offers customers more choice in how they access their income through their retirement. We have a track record of responding well to change and we are well placed to continue to move our business forward."