How InventorySpread works

Newsletter ad arbitrage exists because most newsletter operators with 1,500-8,000 B2B subscribers price their inventory by feel, not by expected affiliate revenue. A $250 primary slot in a 4,000-subscriber B2B SaaS newsletter at a 40% open rate, paired with a HubSpot or Notion affiliate offer, frequently produces $600-$1,200 of expected revenue — a 2.4-4.8× spread.

The scanner

Every 6 hours we read 200+ B2B newsletter rate cards across:

• Paved Marketplace
• beehiiv Recommendations + Marketplace
• Sponsy Booker storefronts
• Passionfroot creator storefronts
• 200 individual "sponsor this newsletter" pages (curated)

For each listing, we compute expected affiliate revenue across 50+ pre-loaded B2B SaaS programs (HubSpot, Notion, Baremetrics, ClickUp, Close, PandaDoc, Webflow, Calendly, and more). The matching algorithm produces:

expected_clicks    = subs × open_rate × 2.5%   // baseline B2B CTR
expected_conv      = expected_clicks × 4%      // default B2B SaaS conversion
expected_revenue   = expected_conv × max(commission_pct × first_year_acv, commission_one_time)
spread             = expected_revenue − slot_price
spread_score       = spread / slot_price
persona_match      = jaccard(listing.tags, offer.tags)
flag IF spread_score > 1.5 AND persona_match ≥ 0.4

The alert

Flagged matches hit your Telegram within 60 seconds of the scrape pass that discovered them. The alert includes:

• Newsletter name, subscriber count, open rate
• Slot price, implied CPM
• Matched affiliate program with commission terms
• Expected revenue, spread multiple
• Booking URL (direct to the newsletter's sponsor page)

Your action

Click through, book the slot, paste in the affiliate offer's creative. Track the outcome (in the dashboard or your own spreadsheet — we provide the Affiliate Tracking sheet in the Operator Toolkit). Capture the spread.

What we ask of you

We're operators ourselves. Two asks:

• Report actual outcomes in the dashboard. We use this to weight the EPC calculation over time — within 4 weeks, the algorithm shifts from aspirational EPCs to your observed EPCs.
• Don't burn newsletter relationships. We never scrape past robots.txt or past a 429. We expect subscribers to behave the same way as buyers.