This gem is not very well maintained. You can check out a new and properlly maintained library for fast XIRR calculation: https://github.com/fintual-oss/fast-xirr

I haven't tried it yet, but I liked two things:

• All calculations are underlying C ( = Fast )
• Bad results return NaN ( = you can decide how to deal with it )

This is a gem to calculate XIRR on Bisection Method or Newton Method.

Add this line to your application's Gemfile:

gem 'xirr'

And then execute:

$ bundle install

Or install it yourself as:

$ gem install xirr

include Xirr

cf = Xirr::Cashflow.new
cf << Xirr::Transaction.new(-1000,  date: '2014-01-01'.to_date)
cf << Xirr::Transaction.new(-2000,  date: '2014-03-01'.to_date)
cf << Xirr::Transaction.new( 4500, date: '2015-12-01'.to_date)
cf.xirr
# 0.25159694345042327 # [BigDecimal]

flow = []
flow << Xirr::Transaction.new(-1000,  date: '2014-01-01'.to_date)
flow << Xirr::Transaction.new(-2000,  date: '2014-03-01'.to_date)
flow << Xirr::Transaction.new( 4500, date: '2015-12-01'.to_date)

cf = Xirr::Cashflow.new(flow: flow)
cf.xirr

# intializer/xirr.rb

Xirr.configure do |config|
  config.eps = '1.0e-12'
  config.days_in_year = 365.25
end

http://rubydoc.info/github/tubedude/xirr/master/frames

Ruby:
 - 2.2.1
 - 2.3
 - 2.4
 - 2.7

ActiveSupport:
 - 4.2
 - 5
 - 6
 - 7

http://puneinvestor.wordpress.com/2013/10/01/calculate-xirr-in-ruby-bisection-method/ https://github.com/wkranec/finance

1. Fork it ( https://github.com/tubedude/xirr/fork )
2. Create your feature branch (git checkout -b my-new-feature)
3. Run specs (rake default)
4. Commit your changes (git commit -am 'Add some feature')
5. Push to the branch (git push origin my-new-feature)
6. Create a new Pull Request