Interest-Only (IO) Securities Best Practices
Overview
This document applies to all releases of Eagle software, covering the details of Eagle Accounting, Data Management, and Performance. Version-dependent functionality is noted with the initial release(s) it became available.
An Interest-Only (IO, also known as stripped) mortgage backed security (MBS) is created from pass-through securities. These MBS pass-throughs strip the cash flow streams into separate IO and principal only (PO) pieces.
On this page
Entity Setup
Take note of fields below when configuring an entity that will trade IOs.
Primary Amortization/Accretion Rule (3197): accounting processes IO amortization (calculating amort yield, cost adjustments, etc.) based on the Level Yield 1 method
This is done regardless of the entity election
Amortization is discussed further in the IO Amortization section of this document
Gain/Loss on Paydowns (1871): select
Amortization
Paydowns on IO securities are for zero cash and do not produce any gain/loss
Eagle Accounting brings down the proportional amount of cost and amortization
This is discussed further in About MBS Interest Only (IO) Processing
This field is required for all entities processing MBS trades
Coupon Spreading Period (637): allows an entity to spread interest income (combination of accrued and amortization) from securities that use a day count basis 30 in the numerator over the
Coupon
period or aMonthly
periodNone
: interest income is posted on a daily basis according to the security’s Day Count Basis (471)The 31st day of the month will have no postings and February 28th will have three days of postings
Coupon
: interest income is spread evenly across the entire coupon periodThe same amount is posted each day of a coupon period
Monthly
: interest income is spread evenly across each monthThe same amount is posted each day within each month, but the daily amount can vary across months
IO Security Amort/Income Flag (17387, V17 R2.8):Â determines how amortization and accretion are recognized on the General Ledger for securities with a processing security type (PST) of Interest Only Factor Based Debt Instrument (DBFBIO)
Select
Separate Income and Amort on Ledger
(INCANDAMORT
) to post interest and amortization separatelyNote: when Coupon Spreading Period is set to
Coupon
orMonthly
, switching the method in this field will result in residual balances in Deferred Interest Income that will need to be cleared with manual ledger entries at the end of each individual DBFBIO security’s coupon period (this is a onetime adjustment after making the change)
Tax Exempt Processing Flag (4948): determines whether income is posted to taxable or tax exempt general ledger accounts; this field works with the security-level Federal Tax Indicator (545) and impacts the Net Investment Income (NII) process when calculating the mixed expense taxable allocation percentage
Yes
: the net distributable income is processed against tax exempt income and expensesIf the security-level Federal Tax Indicator is set to
No
, the system posts the income to tax exempt general ledger accountsIf the security level Federal Tax Indicator is set to
Yes
, the system posts income to taxable general ledger accounts
No
:Â the system posts the income to taxable general ledger accounts
Reference Data
Storage & Configuration
Eagle models each IO security master file (SMF) as a single row in Data Management.
Market Data
Because IOs tend to be risky investments, we recommend using third party (vendor provided) cash flows in Eagle Accounting to generate the most accurate accruals, coupons, and amortization. Third party cash flows come from the market and are inherently intelligent with respect to current market pricing and other relevant information. Refer to Understand Third Party Cash Flows for more information.
If using third party flows is not feasible, we recommend posting impairments over the life of the IO based on your evaluation of the investment
The size of these impairments should be tied to the market where the IO is traded
IOs are a subset of Eagle’s MBS functionality and utilize the same prepayment assumption and factor processing. Refer to the Understand Mortgage-backed (MBS) and Asset-backed (ABS) Securities section of Manage Fixed Income Processing for more information.
Eagle Accounting incorporates prepayment information into the yield calculation used for amortization
Changes/updates to prepayment information affects the amortization yield, and therefore the amortization postings
Use the Prepayment Time Series screens to add or change prepayment information
Eagle Accounting uses a default CPR of 6% and a PSA of 100 if no time series data is added, unless Prepayment Assumption (4518) =
None
has been specified in the amortization rule of the entity trading IO securities
Principal Loss Factors
We recommend not adding Principal Loss Factors for IOs. While Eagle Accounting supports doing so, there is no principal returned to the investor for an IO, thus the functionality should not be invoked.
Zero Coupon
While most IOs are traded at a non-zero fixed or variable rate, a rate of zero can occur in the market. In these cases, 0.0001% (entered as 0.0001
in Eagle Accounting) should be used as both the Coupon (70) on the SMF and Current WAC (1227) in the Prepayment Time Series data. The former prevents a yield calculation error and the latter prevents a missing WAC error.
Security Data
IOs can be set up and maintained using Issue Viewer, Security Reference Manager (SRM), or Reference Data Center (RDC). The list below contains all fields required to configure an IO SMF.
Issue Name (961)
Primary Asset IDÂ (14) & Primary Asset IDÂ Type (1432)
Processing Security Type (3931) =Â
DBFBIO (Interest Only Factor Based Debt Instrument)
This defaults Issue Price (69) and Maturity Price (42) to zero
Issue Country (1418)
Asset Currency (85)
Issue Tax Type (668)
Primary Exchange (17)
Coupon (70): if the fixed rate is zero, use
0.0001
insteadÂCoupon Type (97): typicallyÂ
F (Fixed Rate)
, but all other types are supportedDay Count Basis (471)
Payment Frequency (472)
Delay Days (1799)
Issue Date (68)
Dated Date (1183)
First Coupon Date (473)
Last Coupon Date (474)
Maturity Date (38)
Trading Flat (3949): typically
No
Trade Processing
Open (transaction type = BUY or SHORTSELL)
Trades are entered using the Book Trade module once entity and reference data have been configured. Enter the appropriate entity, security identifier, and trade (35)/settle (37) dates and click Submit to query for the security. Right-click it and select Open > Buy or ShortSell. The list below contains all fields required to book an IO trade.
Original Face (41):Â original par value of the trade (not including any paydowns)
Current Factor (91): looked up automatically based on the most recent Final Factor corporate action announcement
Current Face (40): calculated automatically as Original Face * Current Factor
Price (45): clean unit price
Principal (165): cost associated with the trade (calculated automatically as Current Face * Price * Price Multiplier * Quantity Scale
Price Multiplier (18) and Quantity Scale (19) are typically
0.01
and1.00
respectively
Traded Interest (49): the accrued interest bought (or sold) on the trade
Can be automatically calculated based on Current Face and the security's accrual terms
To enter this data from a trading system, choose an option without
Traded Interest
under Select Values to be calculated by STAR (7000)
Local (50)/Settlement Net Amount (64): the amount of cash that will be moved in local currency terms
Base Net Amount (478): the amount of cash that will be moved in base currency terms
This is calculated using the Local to Base FX Rate (87) that is automatically pulled into the panel
Broker (88)
Close (transaction type = SELL or BUYCVR)
The Book Trade module should also be used to process both full and partial closes. Enter the same identifiers as the open to query for the security. Right-click it and select Close > Sell or BuytoCover depending on whether the existing position is long or short. All fields on the close are the same as the open, except Lot Selection Method (27). This defaults to the entity-level value, but can be overridden.
Gain or loss is realized based on the difference between close price and open price
Accounting
Once an IO trade is booked, it will be picked up in Eagle’s global workflow. Daily accruals and periodic coupon payments are generated as part of the earnings process, Eagle Accounting valuation is calculated when posting unrealized gain/loss, and Data Management valuation is calculated in STAR to PACE. These can be scheduled or triggered manually.
IO Amortization
As mentioned above, Eagle Accounting amortizes IO securities based on Level Yield 1. This method considers the income produced on a debt security (excluding traded interest) to calculate a rate that, when used to compute the present value of all future payments, produces an amount equal to the security’s cost. This rate is the Level Yield and is based on a security’s purchase price, redemption value, time to redemption, coupon yield, and time between interest payments. The Level Yield remains constant through maturity date (unless there are material changes to reference data or amortization rules). Eagle Accounting calculates where the amortization should be, life-to-date, based on the Level Yield and day count of the security. Refer to Manage Amortization and Yield Calculations more information on amortization in Eagle.
In addition to using the Level Yield 1 method, IO securities have a unique approach to posting amortization compared to other securities in Eagle Accounting. Both accrued interest and amortization are posted as a single, netted stream to Interest Income. Amortization is applied using Cost Adjustments (as Referenced in About MBS Interest Only (IO) Processing), which results in no postings to an amortization account.
These are the daily accrual/amortization postings for a standard bond:
DR/CR | Account | Posting |
---|---|---|
DR | Investment Interest Receivable | AAA |
DR | Amortization of Premium | BBB |
    CR |     Cost of Investments |     BBB |
    CR |     Investment Interest Income |     AAA |
For an IO security, amortization is subtracted from Investment Interest Income, so there is nothing posted to Amortization of Premium. Daily accrual/amortization postings for an IO security are below:
DR/CR | Account | Posting |
---|---|---|
DR | Investment Interest Receivable | AAA |
    CR |     Cost of Investments |     BBB |
    CR |     Investment Interest Income |     CCC (= AAA - BBB) |
Coupon Spreading
Since most IO securities use the 30/360 day count basis, funds often elect to spread earnings so that an equal amount is posted each day. The unique approach to IO amortization also affects how deferred is posted when coupon spreading is used. While a normal bond simply spreads the interest receivable, IOs spread both interest receivable and amortization since they get lumped together into Interest Income. As a result, deferred interest will come out of interest income.
Valuation
IOs are valued using real clean prices, entered via Add Issue Price or Pricing Center.
Market Value = Original Face * Current Factor * Price * Price Multiplier * Quantity Scale
Reporting
STAR to PACE (S2P)
Almost all reports in Eagle leverage data from Data Management, which is populated by the S2P process. This will be scheduled as part of the daily workflow, but can also be triggered manually as described in the Accounting section.
The S2P process creates a single row for each IO in the POSITION, POSITION_DETAIL, TRADE, and CASH_ACTIVITY tables. The MARKET_VALUE_INCOME column captures the total market value, inclusive of price fluctuations and period-to-date accruals payable or receivable.
Accounting Reports
Eagle has a core set of accounting reports that can be used to review IO information. These are designed to support the daily operational workflow for business users, allowing Grid Reports to be easily exported to Excel and customized to provide additional details as needed. Advanced Reports are intended to be client-facing and do not provide the same level of customization.
Data Management Reporting
Performance
The performance toolkit has full functionality to calculate market value-based performance for IOs using data supplied by the S2P process. Risk and performance attribution features are available to analyze IO performance.
Automation
IO security master files (SMFs) and trades can be loaded through the standard Message Center streams. The SMF must be loaded prior to the trade (trades do not spawn SMFs). Refer to Supported Generic Interfaces V17 for more information.