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Field notesDeliverability

Why shared sending pools keep landing your email in spam

You bought a sequencer that promised "high deliverability." Two weeks in, your reply rate cratered. The reason isn't your copy — it's the company you keep on a shared IP.

EK
Elise Kirkland
Editor · Banu
Feb 28, 2026 · 6 min
Field notesFeb 28, 2026
98%
Deliverability
inbox placement · custom domain · 3-day warmup

A look at the IP reputation problem nobody at your outreach platform wants to talk aboutWhen Ryan Stenberg took over West Egg Real Estate in late 2024, the brokerage was bleeding cash on three things at once: an Apollo seat per broker, a ZoomInfo enterprise contract, and a Mailshake account that had hit deliverability rock-bottom.

Total monthly outreach spend: $11,200. Total reply rate from those tools: under two percent. The math wasn’t working.

The diagnosis wasn’t copy.

Most consultants would have walked in and rewritten the email templates. Ryan’s hunch was different — and correct. The brokers’ open rates were mid-teens, well below industry. The problem wasn’t what the emails said. It was that they weren’t getting read at all.

“We were sending from a shared IP pool with thousands of other companies. One bad actor and we all eat spam scores.”

Mailshake routes most outbound through shared sending infrastructure. Cheap, easy to onboard — and brutally exposed to the bad behavior of strangers on the same IP block. When the team migrated to BanuMail with a dedicated domain (westegg-cre.com) and a 3-day warmup, inbox placement climbed from 41% to 96% in three weeks.

The numbers, six months in.

Ryan shared the receipts. Apollo and ZoomInfo got cancelled outright; Mailshake followed three weeks after BanuMail warmup completed. The team kept a single tool: Banu. Total monthly cost dropped to $2,200.

Six-month results · West Egg
$9k/mo
Saved
41% → 96%
Inbox rate
1.8% → 6.4%
Reply rate
+11
Closed deals

The reply rate jump — 1.8% to 6.4% — translated to eleven additional closed deals in the first six months. At West Egg’s average commission, that’s mid-six-figures of revenue from a tool change that pays for itself sixty times over.

West Egg Real Estate is a Banu Growth customer. We don’t pay for testimonials and we don’t gate them; Ryan agreed to share these numbers because, in his words, “I wish someone had told me sooner.”

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