```python
from fastapi import FastAPI, Query
import helpers
import asyncio

app = FastAPI()


@app.get("/portfolio")
async def portfolio(symbols: str = Query(...)):
    symbol_list = [s.strip() for s in symbols.split(",")]

    async def _fetch():
        tasks = [helpers.afetch_price(s) for s in symbol_list]
        prices_list = await asyncio.gather(*tasks)
        return {s: p for s, p in zip(symbol_list, prices_list)}

    prices = await _fetch()
    return {"prices": prices}
```