How we source, calculate, and publish our data
Serrari Market Indexes aggregates investment data from regulators, exchanges, and product issuers across Africa. This page explains where each number comes from, how often it updates, and what we do (and don't do) to it before you see it.
Summary
- We don't make up numbers. Every figure on the site traces back to a public regulator, exchange feed, or issuer disclosure.
- We normalize, we don't editorialize. When sources publish in different units or conventions, we convert them so products are directly comparable — but we never adjust the underlying value.
- Data freshness. While we strive to source and display the latest market or provider data, the reporting frequency of some products may not accommodate this — we label the recency as such when displayed.
- Rankings reflect data, not partnerships. No issuer pays for placement. Where two products tie, we break ties by AUM, then alphabetically.
Money Market Funds (MMFs)
Sources
Daily yield announcements published by each fund manager as required by the regulator (the Capital Markets Authority), and quarterly AUM disclosures filed with the CMA.
What we publish
- Daily yield — the annualized rate the manager announced for that business day.
- Effective annual yield — daily yield compounded over 365 days:
(1 + r/365)^365 − 1after management fees have been deducted. - AUM — most recent CMA quarterly disclosure.
Update cadence
Daily yields refresh every business day.
Caveats
Daily yields are gross of withholding tax (15% in Kenya for residents). The "effective" figure assumes the daily rate holds for a full year — actual realised yields will differ.
Bonds & Treasury Bills
Sources
Central Bank of Kenya auction results, CBK indicative bond prices, and Nairobi Securities Exchange secondary-market quotes.
What we publish
- T-bill rates — accepted weighted-average rate from the most recent CBK auction for each tenor (91, 182, 364 days).
- Non-competitive rate — bound directly to CBK auction data.
- Bond YTM — secondary-market yield to maturity for benchmark issues.
- Calculator outputs — net return after 15% withholding tax (T-bills) or 10% (infrastructure bonds), using the auction-day rate, not a smoothed average.
Update cadence
Auction results within 24 hours of CBK publication (typically Thursdays). Indicative bond prices and yields are updated daily.
Caveats
"Indicative" CBK bond rates are mid-prices, not executable quotes. For sums above KES 20M, dealers will quote tighter or wider depending on liquidity.
Equities & indexes (JSE, NGX, EGX)
Sources
Exchange end-of-day feeds (JSE/NGX/EGX via licensed redistributor APIs) and constituent metadata published by each exchange.
What we publish
- Index level & day change — exchange-published close.
- Constituent prices — last traded price, volume, day % change.
- Year-to-date return —
(price_today − price_first_trading_day) / price_first_trading_day, computed locally from the same EOD feed.
Update cadence
EOD after session close.
Caveats
Some metrics for JSE/NGX/EGX (constituent YTD %, ticker change) are still being populated as we expand coverage — affected fields render as "—" rather than fall back to a stale value.
What we do not do
- We do not interpolate missing data.
- We do not republish numbers we cannot trace to a primary or credible secondary source.
- We do not provide investment advice within the page. Methodology pages explain how a number is calculated, not whether you should act on it.
Corrections & change log
Found a number you believe is wrong? Email info@serrarigroup.com with the page URL and the source you'd like us to reconcile against. Methodology changes are logged at the bottom of this page with the date and what changed.
Last reviewed: 2026-05-07.