Mack Investment Securities, Inc.

• A percentage of assets under your management
• Hourly charges
• Fixed fees (other than subscription fees)
• Commissions

Item 5.E lists how the firm is compensated for its advice; Items 5.B, 6.A, and 7.A show whether its people or related companies can also earn commissions. Percentage of assets, fixed, hourly, subscription, and performance-based fees come from clients (a performance-based fee depends on investment results); commissions come with a sale or a trade, often from the company behind the product. How fees, commissions, and other arrangements differ

See the firm's brochure (dated March 31, 2026) for its fees and any account minimum, on the SEC's IAPD site.

$302,589,639 as of October 2026, filing dated March 31, 2026.

A measure of scale, not skill or returns. Discretionary means the firm decides trades; non-discretionary means clients approve each one. What assets under management means

A firm with no individual clients is an institutional manager even if it manages billions; the mix tells you whom the practice is built around.

• Financial planning services
• Portfolio management for individuals and/or small businesses
• Selection of other advisers (including private fund managers)
• Publication of periodicals or newsletters
• Market timing services

Registration

SEC-registered investment adviser. Status as filed: Approved.

Registered since

1987 (39 years)

Employees

Total: 8. Performing investment advisory functions: 8.

Wrap fee program participation

No.

Custodians (Schedule D, Section 5.K(3))

Axos Clearing LLCSEI Private Trust Co.

Custodians holding 10% or more of the firm's separately managed account assets, as filed on Form ADV (Schedule D, Section 5.K(3)). A custodian holds client assets; it does not endorse or supervise the firm. AdvisorCensus has no relationship with any custodian.

Other offices (Schedule D, Section 1.F)

1 other office, as of the April 2026 filing

Oak Brook, IL

States registered or notice-filed

15 states or jurisdictions

AZCACOFLIAILINLAMIMOMSOHTXWAWI

SEC-registered investment advisers are examined by the SEC. SEC, state, and exempt registration

None Reports no disclosure items on Form ADV Item 11. View on IAPD.

Item 11 asks about criminal, regulatory, and civil events involving the firm and its advisory personnel. The detail of each yes answer is on the IAPD record. Reading a firm's disclosures

Regulatory assets under management: $186,261,174 in the October 2021 data and $302,589,639 in the October 2026 data, up 62%.

Total employees: 9 in October 2021 and 8 in October 2026.

As filed in each year's data for the same month. Assets under management move with markets as well as with clients coming and going; they measure scale, not skill or returns. Most firms update these figures once a year.

1. April 2026
   • Regulatory assets under management went from $263,507,750 to $302,589,639 (+15%).

Compared month to month from the SEC's monthly adviser data and the state compilation feed. Owners and control persons are summarized, never named.