Managed vs. Co-Managed SIEM: Operating Model Comparison

Summary

Choosing between Managed SIEM and Co-Managed SIEM is more than a pricing decision — it directly impacts your organization’s visibility, control, and long-term security maturity.

Managed SIEM offers speed and convenience by fully outsourcing monitoring and operations to a third-party provider. Co-Managed SIEM, on the other hand, blends internal ownership with external expertise, allowing organizations to customize detections, develop internal skills, and gradually build a stronger Security Operations Center (SOC).

For organizations looking to mature their security program while maintaining control, Co-Managed SIEM often delivers greater long-term value.

Introduction

When organizations decide to invest in a SIEM platform, one of the first questions they face is not which technology to choose, but how it should be operated.

Most providers offer two models:

• Managed SIEM

• Co-Managed SIEM

Both approaches improve visibility and incident response, but they differ significantly in how much control, customization, and internal capability they provide. Understanding these differences is critical to choosing the right model for your organization, today and in the future.

Why Organizations Look for SIEM Services

Many organizations seek SIEM services because they face similar operational challenges:

• Limited staff managing large environments
  Small or overstretched teams spend more time reacting to alerts than improving security posture.

• Operational overload
  Routine monitoring and maintenance consume engineering hours that could otherwise support innovation.

• Lack of centralized visibility
  Without consolidated log collection and correlation, teams lack insight into trends, blind spots, and emerging risks.

A Security Information and Event Management (SIEM) platform helps centralize logs, correlate activity, and enable proactive threat detection.

Gartner SIEM definition

What Is Managed SIEM?

As its name suggests, managed (also called multi-tenant or SaaS) SIEM is completely handled and operated by a Managed Security Service Provider (MSSP). From the two options, managed SIEM is the most convenient service as the information security provider’s team deploys and monitors your SIEM. Therefore, SaaS SIEM eliminates the need to train your own personnel, and onboarding becomes quicker. 

When companies choose managed SIEM, the MSSP will most likely offer a Security Operations Center as a Service (SOCaaS) subscription. Along with its SIEM, SOCaaS lets organizations outsource their SOC to MSSPs, too. 

You can use managed SIEM, or you can tell the MSSP to service and monitor it on the cloud. If you choose the first option, your IT team has to run and maintain your SIEM. On the other hand, choosing the cloud option eliminates the need for physical infrastructures, such as servers or storage systems. 

Firms in less technical industries and companies that have less time to devote to security practices are likely to outsource their SIEM. The businesses with Managed SIEM are often using franchise-type business verticals. In such cases, the organizations have to comply with different requirements at distributed sites, with the technical work being done centrally within the company. The firms often pair SaaS SIEM with other fully managed services like Unified Threat Management (UTM). 

What Is Co-Managed SIEM?

Co-managed SIEM is a balance between self-managed and a SIEM operated by an MSSP. With this option, organizations have their own on-premises SIEM while a cybersecurity service provider’s team of experts actively helps in the management and monitoring of the customer's SIEM environment. The service provider’s team collaborates with the company’s internal IT team, providing expert advice and information on major security incidents. Therefore, you have more control over your organization’s cybersecurity while the third-party operator reduces your team’s workload. 

Companies like to choose co-managed SIEM when they have a decent in-house IT staff, but they lack the bandwidth to monitor alerts constantly. Such organizations often use the co-managed solution to cut operational costs while they are smaller, but look to move many of the functions in-house as they mature. Co-managed SIEM is also known to be a positive step toward building an SOC within your own IT team. 

Managed vs. Co-Managed SIEM

Before comparing how managed and co-managed SIEM differ, it’s important to understand where they align.
Despite their operational differences, both models deliver core security capabilities that help organizations improve visibility, reduce risk, and support day-to-day security operations.

The following areas highlight what managed and co-managed SIEM have in common.

Both models improve security outcomes, but they serve different organizational goals and maturity levels.

While these shared capabilities establish a strong security foundation, the real distinction lies in how each model operates, specifically in ownership, customization, knowledge retention, and long-term flexibility.

Understanding these differences is crucial when selecting a SIEM model that not only meets today’s needs but also supports the future maturity of your security program.

The Benefits of Co-Managed SIEM

Builds your engineers’ skills and expertise. Instead of “eliminating” your IT team, the co-managed service provider’s team works with your engineers to build their skills and expertise. This can come in handy if you have plans to turn to a self-managed SIEM after a time, but your team doesn’t have the necessary skills.

• Customization. Co-managed SIEM allows for more customization. Therefore, the service provider’s team will work with you to create custom weekly reports on the data you need. You can also ask the firm to run its own ad hoc reports and investigations at any time.
  
  
• Custom tuning and rules. This option also allows custom tuning and rules that apply to the customer’s environment, a useful feature as better custom tuning provides more accurate identification of threats and incidents. And you don’t lose this perk even if you switch to a full in-house IT team later on.
  
  
• Works with you. A co-managed SIEM service provider works with the customer. As the client is a critical part of the escalation chain for incident management, the co-manager couldn’t allow itself to keep the organization in the dark.
  
  
• Quicker problem resolution. The service provider’s team of experts can intervene and resolve operational issues on systems they have access to. This allows for a quick and efficient problem resolution.
  
  If you think increasing the efficiency of your cybersecurity comes with more workload for your employees, then you are wrong. Co-managed engineers will even take over and handle support issues with manufacturers, which can save your staff from being stuck on several multi-hour-long support calls. As your IT team doesn’t need to interact with the manufacturer in such cases, they will have more time to work on productive projects.
  
  
• More flexibility. Compared to managed, co-managed SIEM gives you more flexibility as your company can contact the co-manager’s security experts any time (even with special requests). And more control since your cybersecurity remains in the hands of your IT team.
  
  
• Onboarding. While some parts of co-managed SIEM onboarding are quick, others can take some time. Building management access and evaluating a company’s needs generally takes the same amount of time as with a managed solution. However, the customization that comes with co-managed SIEM can lengthen the onboarding process. 

As managed solutions use only basic, out-of-the-box rules, it will be much quicker to build up the SIEM system in a managed environment. But there is a trade-off: whether the time-efficiency of managed SIEM will be worth it for your company to lose the flexibility and the control that co-managed solutions offer. You should always remember that proper security is neither quick nor convenient.

The Benefits of Managed SIEM

As mentioned before, managed SIEM is more convenient and time-efficient than its co-managed sibling. You don’t have to train your IT team as all your SIEM operations are outsourced to the MSS provider. Also, as this solution takes every SIEM-related task out of your company’s hands, some of your employees can be replaced or re-focused on other operations.

However, managed SIEM often provides you canned “one size fits all” reports that might contain insufficient information for your organization. You need access to new, useful information on your firm’s security, not data that you already know.

As outsourced MSS providers do not work actively with your IT team, they are looking at the network through a keyhole. Therefore, decisions on the severity of network issues are often based on limited knowledge. And this is only one among the many consequences of the managed SIEM operator working for you, but not with you.

Your SIEM tuning stays with the MSSP, which gives you absolutely no information and access to customization perks when you switch providers.

Your Best Fit

We should admit that RedLegg is biased as we offer our clients  co-managed SIEM services. But we truly think co-managed is the better option for many teams looking to build their SOC and looking to continue building their own in-house team.

While we believe co-managed SIEM is better overall, there are some instances when managed would d be a better option for your company. Therefore, you should know the current lifecycle of your business, where it is and where it is heading, and choose the solution you think is the best for your company in its current situation.

Your SIEM, Your Team, Our Flexibility

Already decided to go with co-managed SIEM? Great. Then you’ll get these unique benefits: 

• Take advantage of the service provider’s expertise to improve your team’s skills 

• Custom weekly reports and ad hoc investigations any time, whenever you need them 

• The service provider will work with you, not for you 

• Quick problem resolution 

• Frees up resources for your IT team as the co-manager handles manufacturer issues 

• Custom tuning and rules for more accurate threat and incident identification 

• More flexibility and control 

Remember the following when utilizing a co-managed SIEM solution. You control the situation, not the security provider. 

Contact us to learn more about RedLegg’s co-managed SIEM services.   

Not sure if your current SIEM setup is optimized? Take the first step toward stronger security with our free SIEM Integration Assessment, a no-obligation review by RedLegg experts to identify vulnerabilities and improve performance. Schedule your assessment here. 

Frequently Asked Questions

What’s the difference between managed and co-managed SIEM?

Managed SIEM is fully outsourced to an MSSP, while co-managed SIEM combines internal control with external expertise for greater flexibility and collaboration.

Why would an organization choose co-managed SIEM?

Co-managed SIEM allows organizations to build internal skills, customize detections, and retain ownership while reducing operational burden.

Is managed SIEM better for smaller teams?

Yes. Managed SIEM is often effective for organizations with limited technical resources or those seeking minimal internal involvement.

Does co-managed SIEM help build an internal SOC?

Yes. Co-managed SIEM is commonly used as a strategic step toward developing an internal SOC.

Which option is more cost-effective?

Both models reduce costs compared to building a full in-house team. Co-managed SIEM often delivers greater long-term value through flexibility and skill development.

Want more? Read about...

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• The Cost of Managed SIEM: What Organizations Should Consider