Dan Siroker is a partner at Rebel Fund. He co-founded Optimizely.
What Dan can write
Writes checks of$25K to $500K
Comes in atSeedMostly follows a lead
Ownership target< 5%At first check
Best routeA warm introAsk a founder in their portfolio.
Rebel Fund writes $25K to $500K checks, larger than 1% of firms in the atlas.
Bars: how many firms report each check band. Highlighted: Rebel Fund.Career
- Optimizely · Co-founder
- Rebel Fund · PartnerNow
Companies founded
Optimizely
Also at Rebel Fund
Partners like Dan
At firms with a similar stage, sector and check size.
Alert me when Rebel Fund is active
One email when Dan's firm raises a fund, adds a partner or shows new activity.
Send Mode VC your deck
Raising a pre-seed or seed round? We write $1M to $5M first checks and help founders with distribution. A partner reads every deck.
Send your deckQuestions
Who is Dan Siroker?
Dan Siroker is a partner at Rebel Fund. He co-founded Optimizely.
How much does Dan Siroker invest?
Dan Siroker invests through Rebel Fund, which writes checks of $25K to $500K at seed.
How do I pitch Dan Siroker?
A warm intro from a founder Rebel Fund backed works best.
What did Dan Siroker do before Rebel Fund?
Co-founder at Optimizely.
Last updated 2026-10-15. Is this you? Ask for a correction.