# Percentage Volume Oscillator

`D07-F05-A15` · Technical Indicators → Volume Indicators · archetype `series-transform` · difficulty 2/5 · verification **verified**

Full page: https://docs.thefintechbuilder.com/technical-indicators/volume-indicators/percentage-volume-oscillator/
Agent skill: `npx skills add IslamBaraka90/Fintech-Algorithms-Library` — https://docs.thefintechbuilder.com/guides/agent-skill/

## Install and import

```bash
npm install fintech-algorithms
```

```ts
import { percentageVolumeOscillator } from "fintech-algorithms/technical-indicators/volume-indicators/percentage-volume-oscillator";
```

## Signature

```ts
percentageVolumeOscillator(input)
```

Expresses the gap between a fast and a slow EMA of volume as a percentage of the slow EMA.

## Parameters

| Name | Type | Required | Notes |
| --- | --- | --- | --- |
| `input` | `TopicInput` | yes | `bars` needs `timestamp` and `volume`. From `parameters` this topic reads `fast_period` (default 3) and `slow_period` (default 10, minimum `fast_period` + 1); `period` (default 14) is validated by the family but unused here. |

## Returns

`TopicResult`

`series` holds a single `value`, 100 times the fast EMA minus the slow EMA divided by the slow EMA, and `latest` its last element. A bar whose slow EMA is 0 yields null rather than a division result. The warm-up is set by the slow EMA seed.

## Warm-up

The first ``slow_period` - 1 bars (9 with the default 10)` positions are `null`. `ready_at` is 9 on default parameters.

## Errors

- When `slow_period` is not an integer greater than `fast_period` — throws Error
- When `fast_period` is not an integer of at least 2 — throws Error
- When a bar carries a negative `volume` — throws Error

## Complexity

Time `O(n)`, space `O(n)`.

## Worked example

Captured by running this function on the input its own test provides. Real output of real code — but not asserted against a published figure.

### Input

`input`:

```json
{
  "bars": [
    {
      "timestamp": "2024-01-02",
      "basis": "synthetic-unadjusted",
      "open": 100,
      "high": 101.45,
      "low": 98.695,
      "close": 100,
      "volume": 750000,
      "benchmark": 200
    },
    {
      "timestamp": "2024-01-03",
      "basis": "synthetic-unadjusted",
      "open": 101.49111452,
      "high": 103.38381693,
      "low": 100.05480022,
      "close": 101.78791214,
      "volume": 795117,
      "benchmark": 200.56326135
    },
    {
      "timestamp": "2024-01-04",
      "basis": "synthetic-unadjusted",
      "open": 102.45519048,
      "high": 104.6701838,
      "low": 100.91147007,
      "close": 102.9549389,
      "volume": 840234,
      "benchmark": 201.11020913
    }
  ],
  "parameters": {}
}
```

### Call

```ts
percentageVolumeOscillator(input)
```

### Returns

object with 9 fields: topic_id, title, state, ready, ready_at, series, latest, parameters, …

```json
{
  "topic_id": "D07-F05-A15",
  "title": "Percentage Volume Oscillator",
  "state": "calculated",
  "ready": true,
  "ready_at": 9,
  "series": {
    "value": [null, null, null, null, null, null]
  },
  "latest": {
    "value": 2.367053666955535
  },
  "parameters": {},
  "diagnostics": {
    "causal": true,
    "input_count": 96
  }
}
```

## Verification and provenance

Tier: **verified** (via E).

The worked example below is the figure published in this algorithm's article, replayed and asserted by the test suite on every build. The arithmetic cannot drift without the build failing.

Both tiers guarantee the signature. Full explanation: https://docs.thefintechbuilder.com/guides/verification/

Generated from the docs.json payload shipped inside fintech-algorithms@0.13.0.
The signature and parameter list are checked against the compiled implementation at build time,
so a description that contradicts the code fails the build rather than reaching this file.

## Links

- Article (how it works, step by step): https://thefintechbuilder.com/technical-indicators/volume-indicators/percentage-volume-oscillator/
- Implementation source: https://github.com/IslamBaraka90/Fintech-Algorithms-Library/blob/main/src/technical-indicators/volume-indicators/percentage-volume-oscillator/impl.ts
- Package on npm: https://www.npmjs.com/package/fintech-algorithms
- Domain index for agents: https://docs.thefintechbuilder.com/technical-indicators/llms.txt