Swing pricing

Swing pricing is an anti-dilution mechanism used by many open-ended funds. When net subscriptions or redemptions on a dealing day exceed a threshold, the fund adjusts (swings) the NAV at which all deals are executed: upwards when money is flowing in, downwards when it is flowing out. The size of the adjustment, the swing factor, is set to approximate the bid-offer spreads, taxes and commissions the fund will incur trading the underlying securities.

Two variants exist. Partial swing pricing only applies above a threshold; full swing pricing applies on every dealing day in the direction of net flows. The prospectus states whether the fund uses either, and usually caps the factor (2% is a common maximum, with room to exceed it in stressed markets).

Why it matters

Swing pricing protects long-term holders from paying for other investors' activity, but it also affects the data you see. The published NAV series includes swung prices, so daily performance can appear slightly more volatile than the portfolio itself. For client reporting this explains small discrepancies between a fund's stated return and a client's realised return.

In the API

There is no dedicated swing pricing field; whether a fund swings is a prospectus disclosure. The performance series the API returns is built from the fund's published (swung) NAV history.

json
{
  "indexedPerformance": {
    "points": [
      { "date": "2026-06-27", "value": 131.42 },
      { "date": "2026-06-30", "value": 131.07 }
    ]
  }
}

Example values, indexed to 100 at the series start.

Common pitfalls

• Swing pricing is rarely used by ETFs, where the creation and redemption mechanism performs a similar role in the primary market.
• A swung NAV is not an error in the data. Do not "correct" it against a benchmark.