Inventory Source Lists: Supply Path Optimisation for Your Campaigns

Inventory source lists let you pre-configure which supply-side platforms (SSPs), exchanges, and publishers serve your ads — and how aggressively you bid on each. By creating reusable lists at the advertiser level, you standardise your Supply Path Optimisation (SPO) strategy and apply it to any line item in seconds.

Why Supply Path Optimisation Matters

In programmatic advertising, the same impression can reach your bidder through multiple supply paths — different SSPs, exchanges, or reseller chains. Without SPO, you risk:

• Duplicate bidding — competing against yourself via different paths to the same impression.
• Higher costs — intermediaries add fees at each hop in the supply chain.
• Lower transparency — longer supply chains make it harder to verify where your ads actually run.

Inventory source lists solve this by letting you:

• Select trusted sources — choose the SSPs and exchanges that deliver the best quality and reach for your campaigns.
• Adjust bid multipliers — bid higher on premium, high-performing sources and lower on secondary ones.
• Access Private Marketplace deals — target specific PMP deals with fixed pricing for guaranteed premium inventory.
• Reuse across campaigns — create a list once and apply it to multiple line items without reconfiguring each time.

Key Concepts

Advertiser-Level Asset

Inventory source lists are stored at the advertiser level. Once created, a list is available to every campaign and line item under that advertiser.

Inventory Sources

Each inventory source represents an SSP, exchange, or publisher that supplies ad impressions. ad:personam maintains a curated catalogue of inventory sources, each tagged with:

Buying Type

For each source in your list, you choose a buying type:

Bid Multiplier

Each source carries a bid multiplier (0.1× to 10.0×, default 1.0×) that adjusts your line item's base bid for that specific source:

• 1.0× — bid at the standard rate.
• 1.3× — bid 30 % higher to prioritise winning impressions from this source.
• 0.7× — bid 30 % lower on a secondary source while remaining eligible.

PMP Deals

When a source is set to Deals Only, you select specific PMP deals. Each deal has a deal ID, a label describing the inventory (e.g., "Premium Video — DACH"), a channel (display, video, CTV), a region, and a bid price (fixed CPM). Only sources with available PMP deals show the deals option.

Creating an Inventory Source List

Navigate to Advertiser > Inventory Sources and click Create Inventory List.

Step 1: Name Your List

Enter a descriptive name for the list (e.g., "Premium Video Sources — EU" or "Display Open Exchange — Global").

Step 2: Select Inventory Sources (Left Panel)

The source selector displays all enabled inventory sources in a searchable, filterable table:

• Search — find sources by name.
• Environment filter — filter by Web, App, or both.
• Channel filter — filter by Display, Video, Audio, Native, TV (CTV), or In-App Game.

Each source shows its name, available environments, and supported channels with colour-coded badges. Check the sources you want to include — selections appear immediately in the configuration panel on the right.

Sources are paginated (10 per page) for easy browsing. Use the filters to narrow down to the sources most relevant to your campaign type.

Step 3: Configure Selected Sources (Right Panel)

For each selected source, configure:

1. Buying Type — choose Open Exchange or Deals Only.
   • Switching to Open Exchange clears any selected deals.
   • Switching to Deals Only auto-selects all available PMP deals for that source.
2. PMP Deals (Deals Only) — check or uncheck individual deals. At least one deal must be selected when using Deals Only.
3. Bid Multiplier — adjust the slider or enter a value between 0.1 and 10.0.

You can remove a source from the list using the remove button on each card.

Step 4: Submit

Click Create Inventory List to save. The list is immediately available for use.

Note: Inventory source lists cannot be edited after creation. To update a list, create a new one.

Applying an Inventory Source List to a Line Item

There are two ways to apply an inventory source list:

From the Inventory Sources Table

1. Navigate to Advertiser > Inventory Sources.
2. Find the list and click the Apply action.
3. Select a Campaign and then a Line Item.
4. Click Apply to attach the inventory configuration.

During Line Item Creation or Editing

In the Line Item setup wizard at Step 4: Inventory, you can select inventory sources directly. If you have a pre-built inventory source list, applying it from the Inventory Sources table saves time — especially when the same source configuration is used across multiple line items. See the Campaign Setup Guide for the full setup flow.

Important: Applying an inventory source list is a full replacement operation — it overwrites the existing inventory configuration on that line item.

Featured vs All Sources

When creating a line item, ad:personam pre-selects featured sources by default. These are inventory sources we have vetted globally for quality, reach, and reliability. You can:

• Use the default selection — recommended for most campaigns, especially if you are getting started.
• Create a custom inventory source list — for advanced SPO when you know which exchanges and deals perform best for your audience and formats.

Creating a custom list is particularly valuable when:

• You want to focus budget on a small set of high-performing SSPs.
• You need to include specific PMP deals for premium inventory access.
• You are running campaigns across multiple markets and want different source configurations per region.

Best Practices

• Start with featured sources — ad:personam's curated selection provides strong baseline reach and quality. Customise from there.
• Use bid multipliers to steer budget — instead of excluding secondary sources entirely, lower their multiplier to remain eligible while concentrating spend on top performers.
• Leverage PMP deals for premium inventory — Deals Only mode gives you access to guaranteed, brand-safe placements at known CPMs.
• Filter by channel — when building a list for a Video or CTV campaign, filter sources by the Video or TV channel to ensure every source actually supplies the right format.
• Name lists by purpose — include the market, channel, and strategy (e.g., "DACH Video — PMP Deals") for quick identification.
• Review source performance regularly — use campaign reporting to identify which sources drive the best results and update your lists accordingly.