Detecting Historical Ticker Reuse with Bloomberg Identifiers
Summary
The document explains why a current ticker status or company name may not be enough to identify the security that a ticker represented in the past. Tickers can be reused after a company delists or is acquired, so a present-day lookup may point to a different issuer than the one held historically.
The proposed Bloomberg workflow checks the current market status, then uses a historical point-in-time identifier lookup with a historical date override to retrieve the prior security identifier. Looking up that identifier can reveal the former company and its status. The example demonstrates this with a ticker now associated with an exchange-traded fund but previously tied to a company later acquired. It illustrates security identity research in Bloomberg fields; it does not provide a general automated workflow for identifying every ticker change or acquisition, and the original question's requested Excel output is not fully addressed.
Key ideas
- Tickers may be reused, making current status unreliable for historical issuer identification.
- Bloomberg's current market status field can be supplemented with a point-in-time identifier lookup.
- The historical identifier can be queried to recover the former issuer's name and status.
- The example demonstrates the lookup concept but not a complete bulk screening process.
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Full text
# Using Bloomberg API on Excel to find a stock ticker change/acquisition
# Using Bloomberg API on Excel to find a stock ticker change/acquisition
I am wondering if there is a way in Excel, using Bloomberg API, to find if tickers have changed or acquired by other firms.
For example, given these values,
```
BOFI US (Axos Financial Inc)
EVHC US (Envision Healthcare Corp)
COOL US (PolarityTE Inc)
```
it should return
```
AX US (ticker change on 2018/10/01)
Acquired by KKR on 2018/10/11
PTE US (ticker change on 2018/09/18)
```
respectively.
## Answer by Enrico Schumann (score 2, accepted)
https://quant.stackexchange.com/a/42353
Depending on what you want to do, asking for `MARKET_STATUS` may not be enough, because Bloomberg is reusing tickers. For instance, suppose you have a list of equity tickers that you had in a portfolio some years ago. A stock may have become delisted, but its ticker may subsequently have been given to another stock. In such cases, you may want to check `HISTORICAL_ID_POINT_TIME` as well.
An example, for which I use R; but you can use the same fields in Excel.
```
library("Rblpapi")
blpConnect()
ticker <- "DRIV US Equity"
bdp(ticker, c("NAME", "MARKET_STATUS"))
## NAME MARKET_STATUS
## DRIV US Equity GLOBAL X AUTONOMOUS&ELEC-ETF ACTV
```
But five years ago, that ticker belonged to a different company.
```
bdp(ticker,
"HISTORICAL_ID_POINT_TIME",
overrides = c(HISTORICAL_ID_TM_RANGE_START_DT = "20130101"))
## HISTORICAL_ID_POINT_TIME
## DRIV US Equity 1611364D US
bdp("1611364D US Equity", c("NAME", "MARKET_STATUS"))
## NAME MARKET_STATUS
## 1611364D US Equity DIGITAL RIVER INC ACQU
```Shown in full with attribution under the source's licence. Licence: CC BY-SA 4.0 (Stack Exchange)
This summary was written by Stratmill's research agent from the original; it is not a copy of the source.