Risk Factor — ruling 1

If the target player is an illegal target by the time Risk Factor tries to resolve, the spell doesn't resolve. You don't draw three cards.

Risk Factor — ruling 2

You must still follow any timing restrictions and permissions when casting a spell with jump-start, including those based on the card's type. For instance, you can cast a sorcery using jump-start only when you could normally cast a sorcery.

Risk Factor — ruling 3

A spell cast using jump-start will always be exiled afterward, whether it resolves, it's countered, or it leaves the stack in some other way.

Risk Factor — ruling 4

If an effect allows you to pay an alternative cost rather than a spell's mana cost, you may pay that alternative cost when you jump-start a spell. You'll still discard a card as an additional cost to cast it.

Risk Factor — ruling 5

If a card with jump-start is put into your graveyard during your turn, you'll be able to cast it right away if it's legal to do so, before an opponent can take any actions.

Risk Factor : règles, fonctionnement et interactions (MTG)

Risk Factor is one of those cards players keep asking about. Here is, in plain words, what its official text says, the rulings published by Wizards of the Coast, and the combos players actually run.

Official card text

Target opponent may have Risk Factor deal 4 damage to them. If that player doesn't, you draw three cards. Jump-start (You may cast this card from your graveyard by discarding a card in addition to paying its other costs. Then exile this card.)

How it works : Risk Factor

Original English text — Wizards of the Coast / Scryfall

#1October 5, 2018· Wizards of the Coast
If the target player is an illegal target by the time Risk Factor tries to resolve, the spell doesn't resolve. You don't draw three cards.
No other card is named in this ruling.
#2October 5, 2018· Wizards of the Coast
You must still follow any timing restrictions and permissions when casting a spell with jump-start, including those based on the card's type. For instance, you can cast a sorcery using jump-start only when you could normally cast a sorcery.
No other card is named in this ruling.
#3October 5, 2018· Wizards of the Coast
A spell cast using jump-start will always be exiled afterward, whether it resolves, it's countered, or it leaves the stack in some other way.
No other card is named in this ruling.
#4October 5, 2018· Wizards of the Coast
If an effect allows you to pay an alternative cost rather than a spell's mana cost, you may pay that alternative cost when you jump-start a spell. You'll still discard a card as an additional cost to cast it.
No other card is named in this ruling.
#5October 5, 2018· Wizards of the Coast
If a card with jump-start is put into your graveyard during your turn, you'll be able to cast it right away if it's legal to do so, before an opponent can take any actions.
No other card is named in this ruling.