Gorengan Stocks on the IDX: How a Pump and Dump Works and the Warning Signs
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6 min read
A stock you have never heard of goes up 150% in a week. Your group chat is full of it. Someone says "it is only the start."
You buy. The next week it is down 56% and you cannot sell.
Indonesians have a word for stocks like this: gorengan, meaning "fried snacks". They are hot, cheap and gone fast. Many fit the pattern known as a pump and dump. This post explains how a pump and dump works on the IDX, the warning signs, and what the regulator says about it.
"Gorengan" is slang, not a legal term. There is no official list of gorengan stocks from OJK (the Financial Services Authority) or the IDX (the stock exchange).
In everyday use it means a stock whose price is pushed around by a few big players, not by the business behind it. The sources we found describe the same traits again and again: weak or loss-making companies, thin trading, and sudden extreme price moves (Bisnis.com, via search summary).
Those traits are a rule of thumb. A stock can have all of them and still be honest. A stock can also be manipulated and look healthy. Treat them as reasons to look closer, not as proof.
A pump and dump has two halves. The names say it all.
Reports describe the same pattern: players build a position, push the price up, then sell near the top (Bisnis.com, via search summary).
Here is a made-up example. This is NetWort arithmetic, not a real stock.
A stock sits at Rp100. A pump takes it to Rp250, up 150%. You buy Rp10 juta at Rp250. That is 40.000 shares, or 400 lots. Fees are ignored.
The dump takes the price to Rp110.
| Price | Your Rp10 juta is worth | |
|---|---|---|
| You buy | Rp250 | Rp10.000.000 |
| After the dump | Rp110 | Rp4.400.000 |
You lost 56%. To get back to even, the price must rise from Rp110 to Rp250. That is a gain of about 127%.
None of these proves manipulation. Several together should make you slow down.
1. A big price jump with no news. Check the company's disclosures on the IDX site. If nothing changed in the business, ask why the price did.
2. Trading volume that suddenly explodes. Volume is how many shares changed hands. A quiet stock that suddenly trades heavily deserves a question.
3. Thin trading in normal times. A stock few people trade is easier to push. It is also harder for you to sell when you want out.
4. An IDX "UMA" announcement. UMA stands for Unusual Market Activity. The IDX puts a stock under watch when its price moves outside its usual pattern. The IDX itself says a UMA announcement does not automatically mean a rule was broken (Bisnis.com, via search summary). It means "look carefully", not "guilty".
5. Hype that moves faster than facts. Tips in chat groups and social media posts with no figures. In February 2026, OJK fined a social media figure Rp5,35 miliar for stock manipulation through spreading information online in 2021 and 2022 (Kontan, via search summary).
Market manipulation is against the law in Indonesia. Articles 91 and 92 of the Capital Market Law ban creating a false or misleading picture of trading activity or share prices (Warta Ekonomi, via search summary).
This is not only theory. In February 2026, OJK said it was examining 42 suspected capital market crimes. 32 of them were linked to share trading manipulation, including pump and dump and wash sales (Bisnis.com, via search summary).
A wash sale means trading shares back and forth between accounts controlled by the same group. It makes a stock look busy when no real demand exists.
On 20 February 2026 OJK also fined three parties a total of Rp5,7 miliar over a 2016 case. They were found to have used about Rp92 miliar of fake trading turnover (Kontan and Bisnis.com, via search summaries). Note how long it took: the trades were in 2016, the fine came in 2026. Regulators act, but often long after the money is gone.
We retrieved these reports on 20 October 2026 through search summaries. We could not open the original articles or OJK press releases. Check OJK and the IDX for the full text.
Ask these questions in order:
If you cannot answer the first and third questions, that is your answer.
Do not take a chat group's word for it. Open Explore on NetWort, look up the stock you are curious about, and compare its recent price move and risk figures with similar companies. A price that has run far ahead of its peers, with a very high swing in price, is a cue to read the company's disclosures first.
For another way a stock can freeze on you, read our guide to suspension, auto reject and delisting on the IDX.