ManuelJesus with all due respect to jigglypuff, I feel a bit differently. INSEAD requires the GMAT if it is available in your country, and UC schools prefer, but do not require, the GMAT. Here is my logic.
I am going to take a wild guess that you are Hispanic, which means you are underrepresented. If you bring something to the table in this regard, there is a bit less pressure on your test scores and here's the thing - still, for most schools, the GRE is unpublished. So if they want to add diversity to the school, and it won't "cost" them anything in terms of pulling down average GMAT, they are more likely to admit you.
My R2 French client (underrepresented) had the GRE equivalent of 600 (but he's an engineer, and did well on the quant side. Never did well on either section after taking GMAT 5 times.) He really put our applications in peril but constantly trying to chase after the GMAT instead of focusing on his applications, which was far more within his control. So don't let this happen to you. DO THE APP WELL. Because if they don't like your app, the test score is a moot point.
Ultimately I put my foot down with him and we did turn out some great applications. Despite his test score, he was admitted to Ross with a $40K scholarship and - wait for it - Wharton as well, the prestigious Wharton-Lauder MA/MBA program.
Another Round 2 client did the GMAT and got a 620, but took the GRE the following week with no preparation and received the equivalent of 720. We had already gotten him into the online UNC program but this changed the landscape for him significantly.
What JigglyPuff says about post-MBA is true - in fact, MBB requires 700 if top 10 and 720 if top 10. However I've come to learn from my Round 2 client that BCG is now accepting the GRE as well. If that is your aim, you might need to research this a bit more; would recommend you get in touch with the MBA recruiter at the office where you would want to work.
For IB, they have traditionally wanted to see a 700+ on the GMAT and I am not sure if they are starting to accept the GRE or not. However if you are interested in careers outside of these two, I don't think there will be any penalty to doing the GRE.
Ultimately I might agree that it wouldn't hurt to take the GMAT one more time, if this score is very different from your mocks and you feel confident that you can increase it. But might also want to take a practice GRE exam, there is one available on the MP site.
But don't let this test suck all your time away from other facets of your application. There is time now, but if the next one doesn't go well, the GRE might be a better investment of your time and because it is unpublished, will give you the freedom, in some ways, to show what you can bring to the school in other ways.
Hope this helps!
Farrell
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