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Last Updated: March 8, 2026
DateChangeDetails
March 9Subpenny pricing enabledKXGREENLAND-29 (deci_cent), KXGDPNOM-RUS26 (tapered_deci_cent)
March 12Fractional trading enabledKXJOBLESSCLAIMS-26MAR19, KXHOUHOMEVAL-26MAR19, KXDENHOMEVAL-26MAR19, KXSEAHOMEVAL-26MAR19, KXSDHOMEVAL-26MAR19, KXBOSHOMEVAL-26MAR19, KXUSHOMEVAL-26MAR19, KXCBDECISIONBRAZIL-26APR29, KXCBDECISIONJAPAN-26APR28, KXUE-AUS26APR
March 12Legacy integer fields removed from all API responsesSee removed fields

​
Overview

Kalshi has migrated from integer to fixed-point representation across all APIs. This involves two independent changes:
  1. Subpenny Pricing — price fields use fixed-point dollar strings (_dollars suffix)
  2. Fractional Contracts — contract count fields use fixed-point strings (_fp suffix)
Two fields on Market responses indicate which of these features are active for a given market:
FieldTypeDescription
price_level_structurestringPrice level structure defining price ranges and tick sizes
fractional_trading_enabledbooleanWhether fractional order sizes are accepted

​
Subpenny Pricing

Prices are represented as fixed-point dollar strings. 
{
    "price_dollars": "0.1200"
}
  • *_dollars fields are fixed-point dollar strings with up to 4 decimal places (e.g., "0.1200")
  • When combined with fractional contract sizes, intermediate calculations can reach up to 6 decimal places (for example, in fee rounding math)
Subpenny pricing is offered on a per-market basis. The price_level_structure field on Market responses indicates which pricing tier is active, and the price_ranges array provides the exact valid price intervals and tick sizes for that market.

​
Price Level Structures

StructureRangesTick Size
linear_cent$0.00 – $1.00$0.01
tapered_deci_cent$0.00 – $0.10$0.001
$0.10 – $0.90$0.01
$0.90 – $1.00$0.001
deci_cent$0.00 – $1.00$0.001
tapered_deci_cent provides finer $0.001 (decicent) precision at the tails of the probability range — below $0.10 and above $0.90 — where small absolute price differences represent large relative changes in implied probability. The middle range uses standard $0.01 (cent) ticks. deci_cent applies $0.001 precision across the entire range. See the summary above for the initial subpenny-enabled markets.

​
Fractional Contracts

Contract count fields use fixed-point strings. 
{
  "count_fp": "10.00"
}
  • *_fp fields are strings
  • Accept 0-2 decimal places on input (responses always emit 2 decimals)
  • In requests where both integer and _fp fields are provided, they must match
Check the fractional_trading_enabled field on Market responses to determine whether a given market supports fractional order sizes. See the summary above for the initial fractional-enabled markets. Even if you are not placing fractional orders, you may encounter fractional values in other parts of the API (for example, fills on fractional-enabled markets). One way to prepare is to internally multiply the _fp value by 100 and cast to an integer. For example, treating "1.55" as 155 units of 1c contracts allows continued use of integer arithmetic.

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Fee Rounding

Both subpenny pricing and fractional contracts can produce sub-cent balance changes on fills. When this happens, the exchange applies a rounding fee to restore cent-alignment, and a fee accumulator issues rebates to prevent systematic overpayment. See Fee Rounding for the mechanics and worked examples.

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Removed Legacy Fields

The following legacy integer fields are removed from outgoing REST and WebSocket messages in the fixed-point hard cut. Use the corresponding _fp or _dollars field instead. For the full updated specs, see openapi.yaml and asyncapi.yaml.

​
REST API (/trade-api/v2)

Market (GET /markets, GET /markets/{ticker}):
Removed fieldReplacement
yes_bidyes_bid_dollars
yes_askyes_ask_dollars
no_bidno_bid_dollars
no_askno_ask_dollars
last_pricelast_price_dollars
volumevolume_fp
volume_24hvolume_24h_fp
open_interestopen_interest_fp
notional_valuenotional_value_dollars
previous_yes_bidprevious_yes_bid_dollars
previous_yes_askprevious_yes_ask_dollars
previous_priceprevious_price_dollars
liquidityliquidity_dollars
settlement_valuesettlement_value_dollars
Order (GET /portfolio/orders, POST /portfolio/orders, PATCH /portfolio/orders/{order_id}, DELETE /portfolio/orders/{order_id}):
Removed fieldReplacement
yes_priceyes_price_dollars
no_priceno_price_dollars
fill_countfill_count_fp
remaining_countremaining_count_fp
initial_countinitial_count_fp
taker_fill_costtaker_fill_cost_dollars
maker_fill_costmaker_fill_cost_dollars
taker_feestaker_fees_dollars
maker_feesmaker_fees_dollars
Trade (GET /markets/{ticker}/trades):
Removed fieldReplacement
countcount_fp
priceyes_price_dollars / no_price_dollars
yes_priceyes_price_dollars
no_priceno_price_dollars
Fill (GET /portfolio/fills):
Removed fieldReplacement
countcount_fp
priceyes_price_fixed / no_price_fixed
yes_priceyes_price_fixed
no_priceno_price_fixed
MarketPosition / EventPosition (GET /portfolio/positions):
Removed fieldReplacement
positionposition_fp
total_tradedtotal_traded_dollars
market_exposuremarket_exposure_dollars
realized_pnlrealized_pnl_dollars
fees_paidfees_paid_dollars
total_costtotal_cost_dollars
total_cost_sharestotal_cost_shares_fp
event_exposureevent_exposure_dollars
Settlement (GET /portfolio/settlements):
Removed fieldReplacement
yes_countyes_count_fp
no_countno_count_fp
Candlestick (GET /markets/{ticker}/candlesticks):
Removed fieldReplacement
volumevolume_fp
open_interestopen_interest_fp
BidAskDistribution: open, close, high, lowopen_dollars, close_dollars, high_dollars, low_dollars
PriceDistribution: open, close, high, low, mean, previous, min, max*_dollars counterparts
Orderbook (GET /markets/{ticker}/orderbook):
Removed fieldReplacement
orderbook (legacy integer arrays)orderbook_fp (dollar-priced, fp-count arrays)
Queue Position (GET /portfolio/orders/{order_id}/queue_position):
Removed fieldReplacement
queue_positionqueue_position_fp
Cancel/Decrease Order (DELETE /portfolio/orders/{order_id}):
Removed fieldReplacement
reduced_byreduced_by_fp
OrderGroup (GET /portfolio/order_groups):
Removed fieldReplacement
contracts_limitcontracts_limit_fp
RFQ (GET /rfqs):
Removed fieldReplacement
contractscontracts_fp
target_cost_centi_centstarget_cost_dollars
Quote (GET /rfqs/{rfq_id}/quotes):
Removed fieldReplacement
contractscontracts_fp
yes_bidyes_bid_dollars
no_bidno_bid_dollars
rfq_target_cost_centi_centsrfq_target_cost_dollars
Series (GET /series):
Removed fieldReplacement
volumevolume_fp
IncentiveProgram (GET /exchange/incentive_programs):
Removed fieldReplacement
target_sizetarget_size_fp

​
WebSocket API

orderbook_snapshot:
Removed fieldReplacement
yes (integer arrays)yes_dollars_fp
no (integer arrays)no_dollars_fp
orderbook_delta:
Removed fieldReplacement
priceprice_dollars
deltadelta_fp
ticker:
Removed fieldReplacement
priceprice_dollars
yes_bidyes_bid_dollars
yes_askyes_ask_dollars
volumevolume_fp
open_interestopen_interest_fp
trade:
Removed fieldReplacement
yes_priceyes_price_dollars
no_priceno_price_dollars
countcount_fp
fill:
Removed fieldReplacement
yes_priceyes_price_dollars
countcount_fp
post_positionpost_position_fp
market_position:
Removed fieldReplacement
positionposition_fp
position_costposition_cost_dollars
realized_pnlrealized_pnl_dollars
fees_paidfees_paid_dollars
position_fee_costposition_fee_cost_dollars
volumevolume_fp
rfq_created / rfq_deleted:
Removed fieldReplacement
contractscontracts_fp
target_costtarget_cost_dollars
quote_created / quote_accepted:
Removed fieldReplacement
yes_bidyes_bid_dollars
no_bidno_bid_dollars
yes_contracts_offeredyes_contracts_offered_fp
no_contracts_offeredno_contracts_offered_fp
rfq_target_costrfq_target_cost_dollars
contracts_acceptedcontracts_accepted_fp