Business Functions Library for Excel

    1. Introduction
      1. Introduction
      2. DYear
      3. DMonth
      4. DateYMD
      5. DateSeqNum
      6. IsSeqDate
      7. DayName
      8. MonthName
      9. IsLeap
      10. DaysInMonth
      11. IsAnniversary
      12. WeekNumber
      13. WeekNumberToDate
      14. MonthStart
      15. MonthEnd
      16. NumPers
      17. MostRecent
      18. MostImminent
      19. TimeBaseLengths
      20. AnnSeq
      21. CreateTimeBase
      1. Introduction
      2. DiffY
      3. DiffM
      4. DiffD
      5. DiffP
      1. Introduction
      2. DpY
      3. DpM
      4. DpD
      5. DpP
      6. PrevDateSeq
      7. NextDateSeq
      8. PrevDateList
      9. NextDateList
      10. NextDateCombine
      11. DatePer
      12. EDateBF
      13. DateSeq
      14. DateSeqCombine
      1. Introduction
      2. TpY
      3. TpM
      4. TpD
      5. Occurs
    1. Introduction
      1. Introduction
      2. DpYBD
      3. DpMBD
      4. DpDBD
      5. NextBD
      6. PrevBD
      7. NextDateSeqBD
      8. PrevDateSeqBD
      9. IsBD
      10. NetWorkDaysBF
      11. NextDateListBD
      12. PrevDateListBD
      1. Introduction
      2. Holiday
      3. DescribeHol
      4. WhatHol
      5. IsHol
      6. IsWE
      7. WesternEaster
      8. CreateDate
    1. Introduction
      1. Introduction
      2. MkPmtsSeq
      3. MkPmts
      4. MkPmtsGrow
      5. MkPmtsFcst
      6. MkPmtsSF
      7. MkPmtsLim
      8. MkPmtsLag
      9. MkPmtsLagProf
      10. RePhasePmts
      11. TotPmts
      12. TotPmtsSF
      13. SumBetween
      14. DoBetween
      15. MatchPmts
      16. CarryNeg
      17. CarryPos
      18. MkPmtsX
      19. MkPmtsLagX
      20. MkPmtsIdx
      21. MkPmtsCats
      22. MkPmtsGroup
      1. Introduction
      2. MkPmtsPer
      3. MkPmtsPerGrow
      4. MkPmtsPerFcst
      5. MkPmtsIdxPer
      1. Introduction
      2. MkPmtsGrowMkt
      3. MkPmtsFcstMkt
      4. MkPmtsPerGrowMkt
      5. MkPmtsPerFcstMkt
    1. Introduction
      1. Introduction
      2. GSpread
      3. UniSpread
      4. UniSpreadGrow
      5. SCurve
      6. SCurveGrow
      7. DistSpread
      8. FStepSpread
      9. TStepSpread
      10. MkPmtsWeighted
      11. SCumCurve
      1. Introduction
      2. UniSpreadPer
      3. SCurvePer
      4. SCurveGrowPer
      5. UniSpreadGrowPer
      1. Introduction
      2. WeightSpread
      3. FWeightSpread
      4. TWeightSpread
      1. Introduction
      2. UniSpreadH
      3. SCurveH
      4. WeightSpreadH
      5. FWeightSpreadH
      6. TWeightSpreadH
      7. DistSpreadH
      8. GSpreadH
      9. UniSpreadAdj
      10. SCurveAdj
      11. WeightSpreadAdj
      12. FWeightSpreadAdj
      13. TWeightSpreadAdj
      14. DistSpreadAdj
      15. GSpreadAdj
    1. Introduction
      1. Introduction
      2. Con
      3. ConGrow
      4. AnnGrow
      5. RePhaseCon
      6. AnnRate
      7. ConSF
      8. ConIdx
      9. ConEvent
      1. Introduction
      2. ConPer
      3. AnnGrowPer
      4. ConGrowPer
      1. Introduction
      2. ConGrowMkt
      3. ConFcstMkt
      4. ConFcstGrowMkt
      1. Introduction
      2. ConRevGrow2
      3. ConRev
      4. ConRevGrow
      5. ConRevFcst
    1. Introduction
      1. Introduction
      2. FStep
      3. FStepGrow
      4. FStepGrowX
      5. FStepThenGrow
      6. FStepFcst
      7. FStepGrown
      8. FStepSF
      9. FStepCombine
      10. MultiFStep
      1. Introduction
      2. TStep
      3. TStepGrow
      4. TStepGrowX
      5. TStepThenGrow
      6. TStepFcst
      7. TStepGrown
      8. TStepSF
      9. TStepCombine
      10. MultiTStep
      1. Introduction
      2. FStepGrowMkt
      3. FStepFcstMkt
      4. TStepGrowMkt
      5. TStepFcstMkt
      1. Introduction
      2. FStepRev
      3. TStepRev
      4. FStepRevGrow
      5. FStepRevFcst
      6. TStepRevGrow
      7. TStepRevFcst
      8. FStepThenGrowRev
      9. TStepThenGrowRev
    1. Introduction
      1. Introduction
      2. FittedRate
      3. Ramp
      1. Introduction
      2. InterpedLevel
      3. FittedLevel
    1. Introduction
      1. Introduction
      2. Bal
      3. Level
      4. FLevels
      5. TLevels
      6. FLevelsGrow
      7. TLevelsGrow
      8. FLevelsFcst
      9. TLevelsFcst
      10. FLevelsCombine
      11. FLevelsThenGrow
      12. TLevelsThenGrow
      1. Introduction
      2. FLevelsGrowMkt
      3. TLevelsGrowMkt
      4. FLevelsFcstMkt
      5. TLevelsFcstMkt
      1. Introduction
      2. Grow
      3. GrowFromTo
      4. FGrowStep
      5. TGrowStep
      6. FGrowStepMkt
      7. TGrowStepMkt
      8. GrowMkt
      9. GrowLin
      1. Introduction
      2. Fcst
      3. FcstGrow
      4. FcstCollar
      5. SumFcst
      6. FFcstStep
      7. TFcstStep
      8. IdxFromTo
      1. Introduction
      2. FcstT
      3. TFcstT
    1. Introduction
      1. Introduction
      2. ALevel
      3. FALevels
      4. TALevels
      5. FALevelsGrow
      6. TALevelsGrow
      7. FALevelsFcst
      8. TALevelsFcst
      9. FALevelsThenGrow
      10. TALevelsThenGrow
      11. ALevelGrow
      1. Introduction
      2. FALevelsGrowMkt
      3. TALevelsGrowMkt
      4. FALevelsFcstMkt
      5. TALevelsFcstMkt
      1. Introduction
      2. AGrow
    1. Introduction
      1. Introduction
      2. PVCon
      3. PVAnnGrow
      4. PVConGrow
      5. PVConQ
      1. Introduction
      2. PVTStep
      3. PVTStepQ
      4. PVTStepIC
      5. PVTStepICQ
      6. PVFStep
      7. PVFStepIC
      8. PVFStepQ
      9. PVFStepICQ
      1. Introduction
      2. PVMkPmtsSF
      3. PVMkPmts
      1. Introduction
      2. PVGSpread
      3. PVUniSpread
      4. PVSCurve
      5. PVSCurveGrow
      6. PVDistSpread
      7. PVFStepSpread
      8. PVTStepSpread
      9. PVMkPmtsWeighted
      10. PVSCumCurve
    1. Introduction
      1. Introduction
      2. SimpleToSimple
      3. SimpleToAER
      4. SimpleToCont
      5. SimpleToDF
      6. AERToSimple
      7. AERToCont
      8. AERToDF
      9. ContToSimple
      10. ContToAER
      11. ContToDF
      12. DFToSimple
      13. DFToAER
      14. DFToCont
      1. Introduction
      2. SimpleToSimpleX
      3. SimpleToAERX
      4. SimpleToContX
      5. SimpleToDFX
      6. AERToSimpleX
      7. ContToSimpleX
      8. DFToSimpleX
      9. RateConvert
      1. Introduction
      2. FVM
      3. PVM
      4. PmtM
      5. TermM
      6. IntRateM
      7. PVEGAnn
      8. PVEGAnnM
      9. PVEGPerAnn
      10. PVEGPerp
      11. PVEGPerpM
      12. PVEGPerPerp
      13. SumEGAnn
      14. SumEGAnnM
      15. SumEGAnnCont
      16. SumLGAnn
      17. SumLGAnnM
      18. SumLGAnnCont
      1. Introduction
      2. PVBF
      3. PMTBF
      4. RateBF
      1. Introduction
      2. APRToQuoted
      3. QuotedToAPR
    1. Introduction
      1. Introduction
      2. PVOne
      3. FPVOne
      4. TPVOne
      5. PVOneQ
      1. Introduction
      2. PVA
      3. IRRA
      4. PayBackA
      5. PayBackDiscA
      6. DurationA
      7. AvLifeA
      1. Introduction
      2. PVE
      3. IRRE
      4. PaybackE
      5. PayBackDiscE
      6. DurationE
      7. AvLifeE
      1. Introduction
      2. PVT
      3. IRRT
      4. PayBackT
      5. PayBackDiscT
      6. DurationT
      7. AvLifeT
      8. PVTIC
      9. IRRTIC
      10. PVTX
      11. IRRTX
      12. PVTCX
      13. IRRTCX
      14. PVTR
      15. IRRTR
      1. Introduction
      2. NPVM
      3. IRRM
      4. CorrectionM
      5. CorrectionCont
      6. CorrectionDC
      7. DurationM
      8. AvLifeM
      9. EffTimeM
    1. Introduction
      1. Introduction
      2. Depreciate
      3. DepreciatedValue
      4. DepPoolWIP
      5. DepPoolRatio
      6. DepPool
      7. DepreciatePer
      8. DepreciateGrowPer
      9. DepreciateFcstPer
      10. DepreciateIdxPer
      11. LIFOPrice
      12. LIFOCalc
      1. Introduction
      2. FAvRate
      3. TAvRate
      4. FAvRateTD
      5. TAvRateTD
    1. Introduction
      1. Introduction
      2. LinReg
      3. BestPoly
      4. SignChanges
      5. RSqrdPoly
      6. PolyEqn
      7. CalcPoly
      8. PolyReg
    1. Introduction
      1. Introduction
      2. LookupNum
      3. LookupN
      4. SeekNum
      5. PickNum
      6. SortPick
      7. LookUpNum2D
      8. PickMatrix
      9. LookupNIndex
      10. Seek
      11. SeekList
      12. SortNum
      13. FindIf
      1. Introduction
      2. DoBetweenX
      3. SumCat
      4. SumCats
      5. SumPos
      6. SumNeg
      7. SumDiv
      8. SumBounds
      9. SumSubRange
      10. SumCombine
      11. SelCats
      1. Introduction
      2. Coordinates
      3. WorkSheetName
      4. RefPlus
      5. GetRef
      1. Introduction
      2. MinBetween
      3. MaxBetween
      4. MeanNZ
      5. WeightAv
      1. Introduction
      2. RangeDir
      1. Introduction
      2. SortText
      3. ApplyToList
      4. CombineLists
      5. TransposeNum
      6. Unique
      1. Introduction
      2. Interp
      3. Interpolate
      4. InterpDate
      5. InterpolateDate
      6. Intersection
    1. Introduction
      1. Introduction
      2. Distribution
      3. PartialDependency
      4. DistCumulative
      5. DistUniform
      6. DistTriangular
      7. DistDoubleTri
      8. DistNormal
      9. DistLogNormal
      10. RandNum
      11. NRandom
      12. PickRandom
      13. DescribeDistType
      14. CumProb
    1. Introduction
      1. Introduction
      2. RentGrow
      3. RentFcst
      1. Introduction
      2. FStepRent
      3. FStepRentGrow
      4. FStepRentFcst
      5. FStepRentFcstCollar
      1. Introduction
      2. TStepRent
      3. TStepRentGrow
      4. TStepRentFcst
      5. TStepRentGrowCollar
      6. TStepRentFcstCollar
      1. Introduction
      2. RentFcstR
      3. RentGrowR
      4. FStepRentGrowR
      5. FStepRentFcstR
      6. TStepRentGrowR
      7. TStepRentFcstR
      8. TStepRentGrowSFR
      9. FStepRentGrowSFR
      10. TStepRentFcstSFR
      11. FStepRentFcstSFR
      1. Introduction
      2. CapValue
      3. EqYield
      4. CapValueG
      5. EqYieldG
      6. CapValueGD
      7. EqYieldGD
      8. NomToTrue
      9. TrueToNom
      10. YPP
      11. YPPDef
      12. YPA
      13. YPADef
      14. CapValueGrowGD
      15. CapValueFcstGD
      16. EqYieldGrowGD
      17. EqYieldFcstGD
      1. Introduction
      2. CapValueDCF
      3. EqYieldDCF
      4. CapValueDCFG
      5. EqYieldDCFG
      6. CapValueDCFGD
      7. EqYieldDCFGD
      8. NomToTrueDCF
      9. TrueToNomDCF
      10. YPADefDCF
      11. YPPDefDCF
      12. TheorYield
      13. ImpGrowth
      14. ImpDiscRate
      15. PVRent
      16. TWRR
      1. Introduction
      2. PVRentGrow
      3. PVRentFcst
      4. PVTStepRent
      5. PVTStepRentGrow
      6. PVTStepRentFcst
      7. PVTStepRentGrowR
      8. PVTStepRentFcstR
      9. PVTStepRentGrowIC
      10. PVTStepRentGrowRIC
      11. PVTStepIdxRentGrowR
      12. PVTStepIdxRentFcstR
      1. Introduction
      2. TStepGTurnRentGrow
      3. TStepGTurnRentGrowR
      1. Introduction
      2. IdxRentGrowR
      3. IdxRentFcstR
      4. IdxRentGrowMktR
      5. IdxRentFcstMktR
      6. TStepIdxRentGrowR
      7. TStepIdxRentFcstR
      1. Introduction
      2. LetCostR
      3. LetCostRQ
      4. LeasingFeeGrowR
      5. FServChargeR
      6. ServChargeGrowR
      7. ServChargeFcstR
      8. FServChargeGrowR
      9. FVacServChargeR
      10. VacServChargeGrowR
      11. VacServChargeFcstR
      12. LeasingFeeFcstR
      1. Introduction
      2. UKRatesGrow
      3. UKRatesFcst
      4. UKRatesGrowR
      5. UKRatesFcstR
      6. UKEmptyRatesFcstR
      7. UKEmptyRatesGrowR
      1. Introduction
      2. LeaseEnd
      3. ReletOccurs
      4. RentDateInfo
      5. RentEventOccurs
      6. RentEvent
      7. LastReview
      8. NextReview
      9. LastReviewR
      10. NextReviewR
      11. LeaseInfo
      12. Occupancy
      13. LeaseDates
    1. Introduction
      1. Introduction
      2. Interest
      3. FInterest
      4. TInterest
      5. TotInterestSF
      6. InterestX
      7. PVFInterest
      8. PVInterestX
      9. PVInterest
      1. Introduction
      2. ZeroCoupon
      3. FutureToSpot
      4. SpotToSpot
      1. Introduction
      2. Loan
      3. LoanX
      4. LoanLin
      5. LoanLinX
      6. Mortgage
      7. MortgageQ
      8. LoanPool
      9. MortgagePool
      10. IdxBondGrow
      11. IdxBondFcst
      1. Introduction
      2. Overdraft
      3. CashAcct
      4. FlexAcct
      5. CurrentAcct
      6. STDAcct
      7. LoanAcct
      8. LoanAcctEM
      1. Introduction
      2. BetaIndex
      3. BetaReturns
      4. DescribeReturn
      5. TotalReturn
      1. Introduction
      2. OptionBS
      3. OptionBinom
      4. OptionMonte
    1. Introduction
      1. Introduction
      2. STOIIP
      1. Introduction
      2. Decline
      3. DeclineRate
      4. DescribeDecline
      5. ProdProf
      6. AbandonDate
      7. StartDecline
    1. Introduction
      1. Introduction
      2. MoneyText
      1. Introduction
      2. GetToken
      3. GetTokens
      4. InString
      5. ExInt
      6. ExFl
      1. Introduction
      2. RegSMatch
      3. RegMatchWhole
      4. RegNMatches
      5. RegReplace
      6. RegSMatches
      7. RegSplit
    1. Introduction
      1. Introduction
      2. StdEq
      3. DiffGaps
      4. AddGaps
      1. Introduction
      2. SRound
      3. SFloor
      4. SCeiling
      5. RoundWeekDay
      6. RoundMonthDay
      7. RoundMD
      8. RoundDateSeq
      9. DateRound
      10. DateFloor
      11. DateCeiling
      12. Disperse
      13. RoundList
      1. Introduction
      2. BFVer
      3. DescribeLoanAcctOutput
      4. DescribeCombineSwitch
      5. DescribePmtsPerYear
      6. DescribeLevelSwitch
      7. DescribeBD
      8. DescribeDayCount
      9. DescribePeriods
      10. DescribeLookup
      11. DescribeRounding
      12. DescribeLoanOutput
      13. DescribeShape
      14. ArgValues
      1. Introduction
      2. Switch
      3. SwitchR
      4. SwitchT
      5. SwitchRT
      6. IfElse
      7. IfElseR
      8. IfElseT
      9. IfElseRT
      1. Introduction
      2. CollarDate
      3. InBetween
      4. Collar
      1. Introduction
      2. Ev
Note: In order to use the spreadsheet examples, you need to download Business Functions
RateConvert (FromDatesInt, IntSimple, FromDate, ToDate, [DayCountSource], [DayCountTarget], PrdsSource, PrdsTarget, [MarginOpt])
Generic Rate Convert
Converts an Interest Rate from one basis of compounding to another, taking into account possible irregular compounding periods.
Why we need this function

  • We need this function because sometimes when you are compounding from one interest basis (e.g. quarterly, ACT/365) to another (e.g. semi-annual, 30/360), you can"t do it using the normal algebraic formulae. Often you actually can"t do it without working out the interest in detail for the exact period you are looking at. This function effectively works out the interest on two completely different compounding regimes, and gives the interest rate that makes the Target regime equivalent to the first.
  • Furthermore, where you have a separate margin that is needed for compounding the balance but where you don"t want to compound interest on interest with this margin, the interest calculation has another step in it as the interest and interest on interest is compounded separately.
  • RateConvert is the only generic way to accurately convert a wide range of interest rate types from one basis to another.

Methodology

  • RateConvert is a highly generic function for converting any type of interest rate to any other.
  • It uses proper DayCount and Period definition variables to define both the interest rate you are converting from (the Source) and that you are converting to (the Target)
  • It returns the interest rate applicable to DayCountTarget, ŘPeriodsTargetŘ and ŘIntRatesSimpleŘ, between FromDate and ToDate.
  • The optional MarginOpt variable is to determine how interest on interest is calculated. If you use MarginOpt, this margin is added to ŘIntRatesSimpleŘ to determine the interest, but the interest on interest is only compounded at ŘIntRatesSimpleŘ, without adding any extra margin.

Discussion

Converting from one interest rate basis to another can be extremely complex. For example, many functions in this family deal with the simple case where an interest rate is being converted from a simple interest rate applied at periodic intervals, to an annually in arrears AER (annual equivalent rate) interest rate. These other functions use annuity formulae of the kind (1+r/4)^m-1. These annuity formulae are generalisations and are not accurate when you have specific interest payment dates that may not be at exactly equal intervals, or when you have some of the more exotic daycount conventions.

This function is truly generic, but you need to understand what its doing.

  • First, it calculates the interest between FromDate and ToDate on a example balance of $1000 using ŘIntRatesSimpleŘ and the "Source" parameters. This is simple enough (it actually uses Con).
  • If you use MarginOpt, the interest rate on the balance is (IntRate+MarginOpt) and the interest on interest is at IntRate.
  • Then, it takes a guess at an interest rate for Target (ie the result), and calculates the interest as above.
  • The two amounts of interest are different because the guessed rate is probably wrong. The correct interest rate is determined simply by saying: Result=IntRateGuess*IntSource/IntTarget.

Question

In what circumstances do you need to specify MarginOpt?
Answer:
Say you have a semi-annual rate on a bond that has swap associated with it that resets of a quarterly reference rate (e.g. 3 month LIBOR). You want to convert from a quarterly rate to a semi-annual rate, which involves compounding 2 quarters to make one semi-annual. But whilst you want to compound the balance of the swap at (reference rate+margin), you only want to compound the interest at the time value of money, ie the reference rate. In this case the interest rate you set is the quarterly reference rate, and you set the margin separately. See the example for more information.

Example
RateConvert.xls  

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