Earnest money is the deposit that shows you mean to close. On a wholesale deal it is paid once your offer is accepted, and it counts toward your purchase price at closing.
How much
It varies by market and price. On wholesale deals it is commonly a flat amount, a few thousand dollars and more on bigger deals. The listing and your offer say how much; a larger deposit can make your offer stronger.
When it is due
Usually within one to three business days of the accepted offer or signed assignment. Once an offer is accepted here, both sides see a closing checklist with the due date, and a step that goes late is flagged.
Who holds it
The title company or closing attorney handling the closing, in escrow. Send earnest money to the title company or attorney, never to the wholesaler directly, and confirm wiring instructions by phone with the title company at a number you looked up yourself. Wire fraud targets exactly this step.
When you can lose it
On many wholesale contracts the deposit is non-refundable once any inspection period ends, or from the start. If you back out without a reason the contract allows, expect to lose it. Read the contract terms before you sign, and ask if anything about the inspection period or the deposit is unclear.
This guide is general education, not legal or financial advice.