Inside sales outsourcing might sound like a tongue-twister, but it’s actually one of the most powerful levers organizations can pull when they want to boost revenue. Inside sales is becoming more and more critical to success: data from McKinsey shows that inside sales reps can cover four times the prospects at 50% of the cost, and can unlock 20% more revenue. But if you want to build pipeline and close more deals, you don’t have to scramble to hire more inside reps: you can work with a leading inside sales outsourcing company.
Which partner company should you work with? Everyone promises more meetings, better leads, and faster pipeline growth. But once you look beyond the surface, the differences between providers (and what they can accomplish) are clear.
Whether you’re dealing with low pipeline volume, limited sales bandwidth, or an in-house team stretched too thin, here’s what you need to know about choosing the right inside sales outsourcing company – and the top agencies for you to choose from.
What Inside Sales Outsourcing Actually Includes (vs. SDR-Only Services)
It’s no secret that inside sales works: studies show that inside reps make up at least 40% of high-growth B2B sales teams, and that top teams are using inside sales to expand their reach and penetrate underserved markets. But when you work with an inside sales outsourcing company, what do you actually get?
Outsourcing inside sales typically covers inbound, mid-funnel, and early-stage outbound activity – not just cold calls or booking meetings. Its support is broader than an SDR-only service, which might only touch certain metrics (such as lead generation or appointments booked).
Instead, inside sales outsourcing is designed to keep opportunities moving forward and prevent revenue leakage across the funnel. Here’s what that actually looks like in practice:
- Inbound lead response
When it comes to responding to inbound, speed matters. Research shows that reps that respond first win up to 50% of sales and that businesses that respond within an hour are nearly 7x more likely to have meaningful conversations with decision-makers. Outsourced sales reps handle rapid follow-up on inbound leads, ensuring prospects don’t go cold while waiting for internal reps to get bandwidth.
- Lead qualification + scoring
Not every lead is a good fit for your business, or deserves time with internal AEs. That’s why inside sales reps qualify inbound responses, ask the right discovery questions, and apply consistent criteria, so only sales-ready opportunities move forward.
- Nurture + follow-up sequences
Many deals don’t convert on the first touch – in fact, successful deals often require five or more follow-up calls before they close. Inside sales teams manage structured follow-up and nurture cadences, keeping your brand top of mind during longer decision cycles (without overwhelming your closers).
- Reactivation of stalled opportunities
Pipelines tend to fill up with “almost” deals – prospects who showed interest, then go quiet. Inside sales outsourcing includes re-engagement campaigns to revive conversations that once showed promise, and uncover whether there’s real intent to close.
- Clean handoff to AEs with richer context
Instead of tossing over a calendar invite and hoping for the best, inside sales teams make sure internal reps are poised for a slam dunk: they pass along detailed notes, pain points, timelines, and buying signals. That context helps AEs run better first calls and improves conversion rates downstream.
This broad inside sales approach is where outsourcing really delivers the most value – without requiring you to hire and train new internal reps.
Top Inside Sales Outsourcing Companies
The right B2B sales team outsourcing partner depends on things like your sales motion, target market, and internal bandwidth. Which pipeline problems are you specifically trying to achieve? How much ownership do you want an external partner to take across the funnel?
Here are the top inside sales outsourcing companies on the market – and what each does best.
Inside Sales Solutions (ISS)
Inside Sales Solutions (ISS) is a strong fit for revenue teams operating in complex, high-consideration markets like SaaS, IT services, and cybersecurity – where sales conversations require credibility, timing, and human expertise. Rather than relying on high-volume automation, ISS is built around experienced sales development reps who understand nuanced buying committees and longer decision cycles.
One of ISS’s biggest differentiators is data accuracy. The team works from a human-verified prospecting database that’s continuously maintained, which helps reduce wasted dials, bad emails, and misrouted outreach.
ISS is also known for seamless integration into your existing sales processes. Engagements feel like natural extensions of your internal team, with customized messaging, defined qualification criteria, and clean handoffs
Importantly, ISS offers a range of options: in addition to early-stage outbound, they can manage inbound lead qualification, ongoing nurture, and follow-up, helping teams avoid common gaps where marketing leads stall or fall through the cracks.
CIENCE
CIENCE is a well-known provider in the inside sales and lead generation space, often positioned as a full-service option for companies that want help with prospecting, outbound outreach, and pipeline creation at scale.
Their model blends sales development with research and data services, which can be appealing for teams that need both list building and outbound execution handled externally.
CIENCE is typically a good fit for organizations looking for a structured, repeatable outbound engine and support across multiple channels, especially for teams with clear targeting and messaging already in place.
Martal Group
Martal Group operates with a hybrid, global delivery model, leveraging experienced inside sales reps to support outbound sales development for B2B companies. Their approach emphasizes seasoned talent over entry-level SDRs, which can be attractive for teams selling more complex solutions or targeting senior decision-makers.
Because of their global footprint, Martal Group is often considered by companies looking to expand into new regions or maintain broader market coverage without building international teams in-house.
Belkins
Belkins is recognized for its strength in inbound lead qualification and long-cycle nurture programs, particularly for companies with extended buying timelines.
Their services often focus on managing ongoing follow-up, re-engagement, and structured nurture sequences that keep prospects warm until they’re ready to engage with sales. This makes Belkins a solid option for teams that generate interest but struggle with stalled leads or inconsistent follow-up.
When Does it Make Sense to Work With an Inside Sales Outsourcing Company?
Is inside sales outsourcing right for you? You want to make sure your investment will generate ROI, clear pipeline problems, and lighten the load on your in-house reps. Here are clear scenarios when outsourcing typically makes a lot of sense:
- Pipeline volume: One common trigger for sales outsourcing is insufficient pipeline volume. If your revenue targets are increasing, but inbound leads and outbound capacity aren’t keeping pace, outsourcing can help you add coverage quickly – without the long ramp times of hiring and training.
- Limited sales bandwidth: Many sales teams are stretched thin, forcing them to juggle prospecting, follow-up, and closing at the same time. An inside sales outsourcing partner can take ownership of those early and mid-funnel activities, so your closers can focus on what they do best.
- Speed & flexibility: Hiring internally means committing to salaries, benefits, training, and management – before you know whether the volume or market will justify it long-term. Outsourcing allows you to quickly scale up (or down) faster, test new segments, and support short-term initiatives.
Why Inside Sales Outsourcing Matters Now
Sales teams today are under more pressure than ever. Buying cycles are longer, decision-makers are harder to reach, and internal teams are being asked to do more. That’s where outsourced inside sales can move the needle. By putting experienced outsourced reps in charge of inbound response, qualification, follow-up, and early-stage outreach, companies can maintain momentum – even when internal bandwidth is limited.
That’s where choosing an inside sales agency like Inside Sales Solutions becomes a competitive advantage. If you’re ready to upgrade how your sales organization handles lead flow, nurture, and mid-funnel momentum, partnering with an inside sales outsourcing company like Inside Sales Solutions can help you accelerate growth.