<P> The government pays interest on the bond (1.40% per year as at December 2017). Interest is paid into a fund from which a monthly lottery distributes tax - free prizes to bondholders whose numbers are selected randomly . The machine that generates numbers is ERNIE, for Electronic Random Number Indicator Equipment . Prizes range from £ 25 to £ 1,000,000 . Between 2005 and 2009, there were two £ 1m prizes each month and the minimum prize was £ 50, but prizes were reduced after the 2009 drop in interest rates . A second £ 1m prize was reintroduced in August 2014 . </P> <P> Investors can buy bonds at any time; they have to be held for a calendar month before they qualify for a prize . Numbers are entered in the draw each month, with an equal chance of winning, until the bond is cashed . </P> <P> Winners of the jackpot are told on the first working day of the month, although the actual date of the draw varies . The online prize finder is updated by the third or fourth working day of the month . </P> <P> From 1 January 2009 the odds of winning a prize for each £ 1 of bond was 36,000 to 1 . In October 2009, the odds returned to 24,000 to 1 with the prize fund interest rate increase . The odds reached 26,000 to 1 by October 2013 . As of July 2016, each person may own bonds up to £ 50,000 . Bonds can be bought in units of £ 1 after the first £ 100, with a value of £ 1 per bond and a minimum purchase of 100 bonds (or 50 bonds when paying by standing order). When introduced in 1957 they were popular--the only other similar games were football pools; the National Lottery did not exist until 1994 . In Ireland, the Prize Bond originated in early 1957 . </P>

When do premium bond prize draws take place
find me the text answering this question