A mandatory convertible is preferred stock that turns into common stock on a fixed, published date. Some of the people holding it never wanted common stock: fixed-income funds whose mandates are about income, and convertible arbitrageurs whose trade ends at conversion. The bet was that on the conversion date those holders must dump the shares they receive, into a date everyone can see coming.
forced flow / calendar
Mandatory convertible forced conversion
The idea
How it was tested
No backtest. The entry test read both ends of the chain. First the issuer's terms, to confirm the conversion is compulsory. Then the prospectuses of funds that hold such securities, to see whether owning the common stock after conversion breaks their rules and forces a sale.
Where it died
Rejected on 2026-09-23. The first half held. The preferred "will automatically convert" into common stock on the mandatory conversion date; the holder has no say. But that obliges the holder to end up owning common stock, not to sell it, and only selling moves a price.
The fund prospectuses said the opposite of a forced sale. In one, common stock received through a conversion does not count towards the fund's equity limit. Another states it may hold equity securities received on conversion. As for the arbitrageurs, unwinding a hedge is risk management, not a legal duty, the same shape already rejected for option dealers. A real obligation existed one level up, and it stopped there.
The record
Thesis
On a mandatory conversion date, preferred stock automatically becomes common stock, and holders who do not want equity — fixed-income funds, convertible arbitrageurs — must sell it into a published, hard date.
Gates
Entry test — obligationfail
Is someone actually obliged to trade badly here, and unable to stop?
Why it died
The issuer's obligation is clean ("will automatically convert into a number of shares of our common stock ... on the mandatory conversion date"), but it only obliges the holder to end up owning common stock, not to sell it — and selling is what moves a price. Fund prospectuses say the opposite of a forced sale: common stock received through a conversion "will not count towards" one fund's equity limit, and another "may hold equity securities ... upon conversion". Convertible-arbitrage hedge unwinds are risk management, not a legal compulsion — the same shape already rejected for option dealers.
What it taught
A real obligation one level up (become an equity holder) does not propagate down to the specific action that would create price-insensitive flow (sell). Check the half of the chain that would actually move the price.
Verdict history
- 2026-09-23Rejected at the entry test — holders are not obliged to sell converted shares Rejected before testing