How to Compare Two 13F Filings Using Top-Five Weight, Turnover, and Churn

Comparing two 13F filings correctly means focusing on structure, not spectacle. Holdings count and headline AUM are easy to see, but they are weak comparison tools on their own.

Start With the Top of Book

The fastest useful comparison is top-one, top-five, and top-ten concentration. Those numbers tell you whether the two managers are really running similar risk budgets or just happen to own some overlapping names.

Then Check Turnover and Churn

• Turnover: how much of the capital stack changed quarter over quarter.
• New positions: where the manager widened exposure.
• Exits: where conviction disappeared or implementation changed.
• Overlap: whether the same top names persist across quarters.

Why Holdings Count Is a Trap

A 500-line filing can still be top-heavy. A 60-line filing can still be more balanced than it looks. That is why you should compare managers like FMR or Morgan Stanley by concentration and churn, not by raw breadth alone.

A Better Comparison Sequence

1. Check AUM only for scale context.
2. Measure top-five and top-ten concentration.
3. Look at overlap with the prior quarter.
4. Then inspect what was added, cut, or promoted higher in the book.

What This Prevents

It prevents you from calling two managers similar just because they both own the same mega-cap stocks, and it prevents you from missing meaningful differences in how capital is actually arranged.

FAQ

Should I compare two filings by total holdings first?

No. Holdings count is descriptive, not decisive.

What makes two filings meaningfully different?

Different concentration, different churn, and different persistence at the top of book.

What if both own the same stocks?

The weight distribution still matters. Shared names do not mean shared portfolio identity.

What is the cleanest first-pass metric set?

Top-five weight, top-ten weight, new positions, exits, and quarter-over-quarter overlap.