I'm new to quantlib. I am trying to construct a PiecewiseYieldCurve. I been looking at the implementation of FRA. It seems that the start date of the FRA must be an integer number of month from the valuation date. How do I implement an FRA with a start date that is shifted.

For example,

Valuation date: Jan 9, 2012

Start date of the first 3m FRA: Mar 19, 2012

Rate of the first 3m FRA: 0.01


  • $\begingroup$ I don't think FRA must be an integer number of months from the valuation date. Are you sure you looked the code correctly? $\endgroup$ – SmallChess Jul 23 '15 at 1:25
  • $\begingroup$ The constructor for FraRateHelper's monthsToStart parameter are all integers. $\endgroup$ – user2770287 Jul 23 '15 at 13:25

FRARateHelper takes a number of constructors. You should take a look at the ones that take Period.

The definition for Period is:

class Period {
    : length_(0), units_(Days) {}
    Period(Integer n, TimeUnit units)
    : length_(n), units_(units) {}
    explicit Period(Frequency f);
    Integer length() const { return length_; }
    TimeUnit units() const { return units_; }
    Frequency frequency() const;
    Period& operator+=(const Period&);
    Period& operator-=(const Period&);
    Period& operator/=(Integer);
    void normalize();
    Integer length_;
    TimeUnit units_;

Period encapsulates a time-frame, the frame can be specified by Days. In your example, you might want to do something like:

int days = Actual360(Mar 19, 2012 - Jan 9, 2012)
Period p = Period(days, Days)
FRARateHelper(0.01, p, ...)

The pseudo-code should give you enough information to complete your code. You'd decide a day-counting convention, and use it to count number of days, then use the Period class to start FRARateHelper.

  • $\begingroup$ I forgot to mention that I'm using the C# version instead of C++ and that feature isn't implemented in C#. So I implemented it myself. $\endgroup$ – user2770287 Jul 24 '15 at 13:36

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