GP wants the right to admit new capital ahead of me on a capital call

Price it as a call option the sponsor holds against your position, struck at zero. The value to them is highest when the property is impaired, which is exactly when it gets exercised, so assume the worst case version rather than the polite one.

Work the arithmetic. Say the deal needs $2M eighteen months in, you're 3 percent of the $11.5M, and you decline. If new money comes in at a 12 percent pref with a senior return of capital, the first $2M plus accrued pref out of any sale goes to them before your $11.5M class sees a dollar of capital back, and your 8 percent has been accruing all along on a claim that now sits second. On a modest exit your accrued pref becomes decoration. Your economic outcome isn't diluted by the ratio of new dollars to old dollars, it's determined by the priority ordering. That's the part vellum spotted and it's the right read.

The more standard version is materially better on three counts you can actually negotiate. A stated ceiling on the rate the rescue capital can carry. Pari passu treatment rather than senior, so new money shares the return of capital line instead of jumping it. Non-funding LPs diluted by a defined formula, often a 1.25x to 2x penalty on the unfunded amount, rather than by whatever the manager writes that day.

Keystone is right that the cap expiry is the trigger and you should model the call as probable rather than remote. Two more things to establish in writing: whether the sponsor's own co-invest is subject to the same call and the same dilution, and whether affiliate fees get deferred before capital is called from LPs. A sponsor who will suspend their asset management fee before diluting you is telling you how they'll behave. Have securities counsel read 4.4 alongside the definitions of Class A interests and Distributable Cash, since the definitions often change what the clause appears to say.