Market prices

How the index is built

The index is the weekly median price per gigabyte for each generation, module type and capacity, computed only from deals where money moved and the buyer confirmed the count. Here is every rule, in order.

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Source: Released deals only; Paid, shipped, confirmed, funds released. Never asking prices
Period: ISO weeks; Monday to Sunday, keyed by the day the money released
Minimum per point: 3 deals; Fewer and the week stays unpublished
Outlier rule: 3 × IQR; Against the trailing eight weeks; held out and reviewed by a person

What counts as a deal

One rule: the deal is finished.

A deal enters the index when the funds have been released to the seller: the buyer paid the platform, the seller shipped on our label, and the buyer confirmed the count or 3 business days passed after delivery without a dispute. Deals that ended in a refund are excluded; a split outcome enters at the amount actually released.

Nothing else counts. Not asking prices, not unsold lots, not floor offers that were declined, not deals reported to us by anyone. The house account’s deals count once, like anyone else’s, and the house has no view of a point before it publishes.

The weekly statistic

Price per gigabyte, so a 16GB module and a 64GB module can be compared, and a median, so one deal cannot move it.

For each deal: $/GB = hammer ÷ (modules × GB per module). Shipping, fees and premiums are not in it. For each generation, module type and capacity with enough deals in the week, the index publishes the median, the 25th and 75th percentiles, the number of modules sold and the number of deals.

Deals are weighted equally, not by size. A tray of 50 and a pallet of 2,000 are each one observation; the module count is published beside the median so you can see the week’s volume.

A worked week, in index units (not prices)

Held out: 171 sits outside 3 × the interquartile range of the trailing weeks, so it is flagged for a person to review.
Median: The middle of the remaining 6 deals: 104. The highest and lowest deals cannot move it.
Published: 6 deals clear the 3-deal minimum, so the point publishes with its P25, P75, modules and deal count.

Outliers

A rule, then a person. Never a silent drop.

A deal is flagged when its $/GB falls outside the trailing eight weeks’ quartiles for the same series widened by 3 × the interquartile range. Flagged deals are held out of the week and reviewed by staff, who keep or exclude them with a written reason. Every decision is audited and reversible.

A week with an unresolved flag does not publish until it is resolved, so a point is never a number that one odd deal, or one buyer, could move.

When a point publishes, and revisions

Weeks roll up on Monday morning. Thin weeks wait.

Each ISO week rolls up on Monday morning, keyed by the day the money was released. A point publishes when it has at least 3 deals and no unresolved outlier. Thinner weeks stay unpublished rather than publish a number one buyer could move; the trend chart shows them as gaps.

Staff can publish or unpublish a point with a reason, for example when a late dispute reverses a deal. Unpublished points never appear on the pages, in the widget, in the CSV or in reserve suggestions. The CSV carries a publication timestamp per row so a revision is visible.

What the index cannot tell you

A median of real deals is honest; it is not a quote.

Mix effects. A series groups modules by generation, module type and capacity; speed, rank, manufacturer and condition grade still vary inside it. A week heavy with tested OEM pulls prices higher than a week of untested stock, with no change in the market.

Thin series. A point at the minimum deal count is a handful of trades. Read the deal count beside the median and the width between P25 and P75 before you lean on it.

Lag. The index records when money released, which is days after the hammer. In a moving market the latest week trails the room.

One venue. These are deals on this site between verified businesses with protected payment. Other channels price differently, and that is part of what the index measures.

Citing the index

Quote it in a listing, an offer or a report. Credit it and say which week.

Credit “Memory Traders price index” with a link to the page you used, and name the week (for example the Monday date in the CSV). The licence is CC BY-NC 4.0: free for non-commercial use with attribution; email us for commercial use, which we usually allow with the same credit.

For a live figure on your own site, use the widget. For your own analysis, members can download every published week.

Questions people ask

Why is a week missing for the module I care about?

A point publishes only when at least 3 released deals for the same generation, module type and capacity closed in that week and no outlier is unresolved. A thin week stays unpublished rather than publish a number one buyer could move.

Are asking prices or unsold lots included?

No. Only released protected-payment deals count: the buyer paid the platform, the seller shipped on our label, the buyer confirmed the count or the window lapsed, and the funds were released. Nothing is estimated, scraped or self-reported.

Can a point change after it is published?

Only by a staff action with a written reason, which is audited. A late dispute that reverses a deal can lead to a revision; the CSV carries the publication timestamp so you can see when a row changed.

Can I quote the index in a listing or an offer?

Yes. Credit "Memory Traders price index" with a link to the page, and say which week. The licence is CC BY-NC 4.0 for non-commercial use; email us for anything else.

Does ITAD Authority’s own trading move the index?

House deals are released deals like any other and count once. The house cannot bid on its own lots and gets no early data, so it cannot see a point before you do.