I am using the "Bond" function in QuantLib-Python 1.14.

I am planning to use it in this way:

BondPtr::BondPtr(Natural,Calendar const &,Date const &,Leg const &)

I tried to construct the last parameter as ql.Leg((cf1,cf2,cf3,cf4))

where cf1=ql.SimpleCashFlow(3,ql.Date(25,1,20XX)), cf2=..., cf3=..., cf4=...

Finally, I got the error:

RuntimeError: no coupons provided

Can someone one tell me how to make it correct? Thank you a lot!

Here is my code for reference:

import QuantLib as ql cf1=ql.SimpleCashFlow(3,ql.Date(25,1,2019)) cf2=ql.SimpleCashFlow(3,ql.Date(25,1,2020)) cf3=ql.SimpleCashFlow(53,ql.Date(25,1,2021)) cf4=ql.SimpleCashFlow(51.5,ql.Date(25,1,2022)) couponsLeg=ql.Leg() couponsLeg.push_back(cf1) couponsLeg.push_back(cf2) couponsLeg.push_back(cf3) couponsLeg.push_back(cf4) newBond=ql.Bond(0,ql.UnitedStates(),ql.Date(25,1,2018),couponsLeg)

  • $\begingroup$ My purpose is to construct a bond with advanced principle payment (I have added my code for reference). I have read the C++ code, I am not clear whether I used the ql.Leg() correctly. $\endgroup$
    – user38862
    Commented Feb 19, 2019 at 12:00

1 Answer 1


The problem is that the Bond constructor expects a leg of coupons and you are giving it a leg of simple cashflows.

You can build it like this (the redemptions will be assumed from the coupons):

dc = ql.Thirty360()
cf1 = ql.FixedRateCoupon(ql.Date(25,1,2019), 100, 0.03, dc, ql.Date(25,1,2018), ql.Date(25,1,2019))
cf2 = ql.FixedRateCoupon(ql.Date(25,1,2020), 100, 0.03, dc, ql.Date(25,1,2019), ql.Date(25,1,2020))
cf3 = ql.FixedRateCoupon(ql.Date(25,1,2021), 100, 0.03, dc, ql.Date(25,1,2020), ql.Date(25,1,2021))
cf4 = ql.FixedRateCoupon(ql.Date(25,1,2022), 50, 0.03, dc, ql.Date(25,1,2021), ql.Date(25,1,2022))
couponsLeg = ql.Leg([cf1, cf2, cf3, cf4])

Or, better yet, you can simply use the AmortizingFixedRateBond class:

notionals = [100,100,100,50]
schedule = ql.MakeSchedule(ql.Date(25,1,2018), ql.Date(25,1,2022), ql.Period('1y'))
bond = ql.AmortizingFixedRateBond(0, notionals, schedule, [0.03], ql.Thirty360())

Both would output the same cashflows, which I believe is what you want:

January 25th, 2019 3.0
January 25th, 2020 3.0
January 25th, 2021 3.0
January 25th, 2021 50.0
January 25th, 2022 1.5
January 25th, 2022 50.0


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