I am trying to understand a discrepancy among a few stock split data sources. One such example is HLT's split on 2017-01-04 (see https://ir.hilton.com/spin-off-information). On this date, HLT spun off into HLT, PK, and HGV. Investors received 0.2 PK and 0.1 HGV for each HLT. HLT then had a 1:3 reverse split to bring the trading price back up.
The NASDAQ's splits calendar shows a 1:3 ratio, however Yahoo Finance and splithistory.com both list a 1000:2052 ratio instead. Seems this latter split is accounting for the spinoff somehow. How do they arrive at 1000:2052... is that some officially published number? I am unable to figure out how they got that.
My attempts at reproducing that ratio: HLT closed 2017-01-03 at $27.39, and opened 2017-01-04 at $57.3. That's a 1:2.092004381 ratio, so doesn't quite line up. From this link it seems "when issued" tickers PK-WI and HGV-WI started trading ~21 days prior. My guess is NYSE took the closing prices for those on 2017-01-03 to calculate the split ratio to apply the morning of the 4th. E.g A ratio of
27.39 : 3*(27.39 - close(PK-WI) - close(HGV-WI)). However, I can't find any historical data for those when-issued shares, so can't verify if that gives us 1000:2052. Just seems there would be some central, officially published split ratios that the exchange applied to magically update the price.