Fiva case study: fund return estimate infrastructure

Project summary
Who it is for	Individual investors who want to follow funds, stocks and other markets in one app (Fincode's own product)
Product	Investment analytics app; no trading
Platforms	iPhone (beta via TestFlight); browser version Fiva Web in preparation (appfiva.com)
Markets	BIST, NASDAQ, European exchanges, Turkish mutual funds (TEFAS), pension funds, ETFs, gold, FX, commodities, crypto assets
Language	Turkish only
Developer	Fincode Yazılım ve Teknoloji A.Ş.

The problem Fiva addresses

Turkish mutual fund prices are published at the end of the day; under the Capital Markets Board (SPK) Communiqué III-52.1, a fund's unit price is, as a rule, calculated and announced daily. An investor who wants to know how a fund is moving during the day has to wait until the evening. The same investor usually follows stocks, funds, pension funds, gold, FX and crypto, company disclosures on KAP (Turkey's public disclosure platform) and the economic calendar in separate places.

Fiva addresses both needs: it estimates each fund's daily return with a model before the price is final, and it gathers market data in a single app. Fiva provides data, analysis and tools; it executes no trades, and investment decisions remain with the user. The product page is at Fiva.

What the product includes

Module	What it does
Fund return estimates	Daily return estimate before the price is published, the time the price becomes final and the historical accuracy rate of each estimate; comparison with indices such as the BIST 100; similar estimate screens for BIST and NASDAQ stocks
Daily summary	What changed since the last visit; economic calendar, KAP disclosures, dividend and capital increase calendars, IPOs and news ranked by importance
Global markets	Stocks and sectors on BIST, NASDAQ and European exchanges; mutual funds, pension funds, ETFs, gold, FX and commodities
Charts and technical analysis	Multiple time frames, market breadth, the day's biggest movers and the reasons behind stocks hitting daily price limits
Macroeconomic data	Cross-country maps of inflation, policy rates and growth; loan and deposit rates by bank; crypto exchange volumes and market shares
Watchlists and alerts	Personal watchlists, price alerts, notes and ready-made smart lists that filter by criteria
Fund analysis tools	Fund comparison, screening, scenario testing and a returns race screen
Investor community	Users share ideas and forecasts; forecast results become visible when their period ends
Fiva AI	An AI assistant that can take into account the portfolio information users enter and can create tasks for them

Fund return estimation: the general engineering approach

Fiva's estimates are model-based, and the model's internals are not described on this page. This section explains the general engineering frame of the fund return estimation problem.

A fund's unit price is its total value divided by the number of units outstanding. The core idea of an intraday estimate is to revalue the fund's last known portfolio at intraday prices, which requires three layers of data:

Holdings: funds publish their month-end holdings on KAP in a portfolio distribution report; under SPK Communiqué II-14.2, these reports are disclosed within six business days after the month ends. TEFAS, Turkey's fund trading platform, shows portfolio distribution by asset class.
Prices: intraday prices and exchange rates for the holdings arrive from different markets in different time zones.
Valuation rules: the estimate is designed to track the prices the fund will actually use in the evening, such as closing prices, the time at which FX rates are fixed and the method for instruments that did not trade.

The engineering challenges come from the weak points of these layers. A month-end snapshot ages as the manager trades; bonds, repos and deposits have no intraday price; FX and foreign prices are fixed at different times; on dividend or bonus-share dates an unadjusted base price shows a loss that did not happen; and in funds of funds, errors in the underlying funds compound.

How accuracy is shown

Fiva shows the historical accuracy rate next to every estimate, along with the time at which the price becomes final. An estimate is therefore read together with its track record, and users can judge its reliability themselves.

In this kind of accuracy measurement, each estimate is compared with the actual return calculated from the price published that evening. Typical measures include the mean absolute deviation, the share of days on which the direction was right, and the share of days on which the error stayed within a set band. The estimate and the price must be matched to the same valuation date, and the measures are read by fund type: money market fund prices rise almost every day, so directional accuracy says little on its own.

Past accuracy does not guarantee the accuracy of future estimates, and an estimate never replaces the official end-of-day price.

Data, delays and licensing

The app's "Data and Delays" section states which data is real-time and which is delayed. In a market data product this distinction is contractual as much as technical: according to Borsa Istanbul, distributing its data requires a license as a Distributor or Sub-Distributor, and delayed data is among the data types a sub-distributor can be authorized to distribute. Data agreements therefore decide what can be shown with which delay; the product's job is to let users see how current the data in front of them is.

Combining BIST, NASDAQ and European markets in one app also calls for a shared data layer. At this scale, symbol mapping, trading hours and time zones, holiday calendars, corporate actions and event data such as company disclosures have to be reconciled into one consistent model. Similar multi-source data work is part of Fincode's exchange API integration service.

Responsible product principles and current status

Fiva executes no trades and gives no investment advice.
Estimates are model-based, may be wrong and are not buy or sell recommendations.
Community posts belong to their authors and are not verified by Fincode. Under the terms of use, offers of unauthorized investment advice, paid signals or portfolio management, and false or misleading posts that may amount to market manipulation, are prohibited.
Fiva AI gives no buy, sell or personalized investment recommendations; its purpose is to help users find the information they need before deciding, faster.
Screenshots are for illustration only and do not recommend any fund or stock.

As of October 2026, Fiva is in beta for iPhone and available through a TestFlight invitation; the app is in Turkish only. Apple's TestFlight is used to distribute pre-release builds to testers and collect their feedback. Fiva Web, the browser version, is being prepared at appfiva.com; it also gives no investment advice and executes no trades.

How success is measured

For Fiva, success criteria center on the accuracy and transparency of the information users see:

Estimate errors tracked separately by fund type, with historical accuracy shown next to every estimate
Errors on special days, such as dividend dates, holidays and FX fixing effects, reviewed separately
Every data point correctly labeled as real-time or delayed
Community and Fiva AI content designed so that it does not amount to investment advice
Feedback from beta users reflected in the product

Frequently asked questions

Can I trade through Fiva?

No. Fiva is an investment analytics app that provides data, analysis and tools; it does not execute trades.

How reliable are the fund return estimates?

Each estimate is shown with its historical accuracy rate so users can judge it. Estimates are model-based and may be wrong, and past accuracy does not guarantee future accuracy.

Which devices and languages does Fiva support?

As of October 2026, Fiva is in beta for iPhone through TestFlight and is available in Turkish only. A browser version, Fiva Web, is being prepared at appfiva.com.

Does Fiva give investment advice?

No. Nothing in the app, the community or Fiva AI answers constitutes investment advice; investment decisions remain with the user.

Sources

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