I have a friend flying SYD-LAX later this year on a Virgin-operated flight.

I have a friend flying SYD-LAX later this year on a Virgin-operated flight. He’s in Premium Economy and would like to be in Business.

They’re still selling Business seats on the flight, and he rings every so often to ask for an upgrade (using his points) only to be told there are no upgrade seats available.

He has been able to register an “UpgradeMe Premium Bid” on the website, but would prefer to use points than pay cash for the upgrade.

Can anyone explain the process Virgin might be following here, and whether all PremiumBids are likely to be fulfilled before any remaining seats are then offered for Points-based upgrades?

No. The points based upgrades are given out of the reward seat bucket. If you can see a reward seat on that flight you can upgrade.

Upgrade me usually is just a sell off of the unsold seats. 

Is your friend a Gold or Platinum Velocity member? Silver and Bronze members cannot upgrade using points until just before the flight takes off basically (dependent on seat availability and other upgrade requests at the time 24hours prior to departure)

I was in a similar situation with VA, and I managed to pick up SYDAUH for somewhere around $750-800. Mind you, in was in about the September-October period. SYDLAX might be a different story because of demandbeing higher, but also might be in your favour that they fly every day on this route (unlike SYDAUH which they drop at the slightest whim, for maintainence.) @jared was on the mark about the buckets - unless someone with a points-upgrade cancels their reservation, there's little to no hope of getting it on points.